View source for Email spam

{{Short description|Unsolicited messages sent by email}}
[[Image:spammed-mail-folder.png|thumb|300px|An [[email box]] folder filled with spam messages]]
'''Email spam''', also referred to as '''junk email''', '''spam mail''', or simply '''spam''', refers to unsolicited messages sent in bulk via [[email]]. The term originates from a [[Spam (Monty Python)|Monty Python sketch]], where the name of a canned meat product, "[[Spam (food)|Spam]]," is used repetitively, mirroring the intrusive nature of unwanted emails.<ref name=DfnSpam>{{cite dictionary|url=http://www.merriam-webster.com/dictionary/spam|dictionary=[[Merriam-Webster Dictionary]]|title=spam}}</ref> Since the early 1990s, spam has grown significantly, with estimates suggesting that by 2014, it comprised around 90% of all global email traffic.<ref name="MAAWG.org">{{cite web|date=November 2014 |url=http://www.maawg.org/email_metrics_report
|access-date=3 November 2017|archive-date=2015-04-03
|archive-url=https://web.archive.org/web/20150403181626/https://www.m3aawg.org/email_and_bot_metrics_report|url-status=live
|title=M{{sup|3}}AAWG Email Metrics Program: The Network Operators' Perspective; Report #16 – 1st Quarter 2012 through 2nd Quarter 2014
|publisher=Messaging, Malware and Mobile Anti-Abuse Working Group (M{{sup|3}}AAWG)}}</ref><ref name=JNCA-2014>{{Cite journal |last1=Fu |first1=JuiHsi |last2=Lin |first2=PoChing |last3=Lee |first3=SingLing |date=2014-08-01 |title=Detecting spamming activities in a campus network using incremental learning |url=https://www.sciencedirect.com/science/article/pii/S1084804514000630 |journal=Journal of Network and Computer Applications |language=en |volume=43 |pages=56–65 |doi=10.1016/j.jnca.2014.03.010
|issn=1084-8045 |access-date=2022-10-30 |archive-date=2020-04-30
|archive-url=https://web.archive.org/web/20200430111059/https://www.sciencedirect.com/science/article/pii/S1084804514000630
|url-status=live |url-access=subscription }}</ref>

Spam is a burden for the recipient, who may be required to manage, filter, or delete these unwanted messages. This cost imposed on recipients, without compensation from the sender, makes spam an example of a "[[negative externality]]" (a side effect of an activity that affects others who are not involved in the decision).<ref name=EconSpam2012>{{citation|title=Economics of Spam|journal=Journal of Economic Perspectives|volume=26|issue=3|pages=87–110|doi=10.1257/jep.26.3.87|year=2012|last1=Rao|first1=Justin M.|last2=Reiley|first2=David H.|doi-access=free}}</ref>

The legal definition and status of spam varies from one jurisdiction to another, but laws and lawsuits have not generally been successful in stemming spam.<ref>{{Cite news |date=2024-08-19 |title=Email Unsubscribe Services Don't Really Work. Follow This (Free) Advice Instead. |url=https://www.nytimes.com/wirecutter/reviews/best-email-unsubscribe-service/ |access-date=2025-03-06 |work=The New York Times |language=en-US |issn=0362-4331}}</ref>

Most email spam messages are commercial in nature. Whether commercial or not, many are not only annoying as a form of [[attention theft]], but also dangerous because they may contain [[Html email#Security vulnerabilities|links]] that lead to [[phishing]] web sites or sites that are hosting [[malware]] or include malware as file [[email attachment|attachments]].

Spammers collect email addresses from chat rooms, websites, customer lists, newsgroups, and viruses that harvest users' address books. These collected email addresses are sometimes also sold to other spammers.

==Overview==
At the beginning of the Internet (the [[ARPANET]]), sending of commercial email was prohibited.<ref name="Stacy1982">{{cite web |last1=Stacy |first1=Christopher |title=Getting Started Computing at the AI Lab |url=https://dspace.mit.edu/bitstream/handle/1721.1/41180/AI_WP_235.pdf?sequence=4 |publisher=MIT |access-date=2018-10-15 |archive-date=2019-03-23 |archive-url=https://web.archive.org/web/20190323132534/https://dspace.mit.edu/bitstream/handle/1721.1/41180/AI_WP_235.pdf?sequence=4 |url-status=live }}</ref> Gary Thuerk [[History of email spam|sent the first email spam message]] in 1978 to 600 people. He was reprimanded and told not to do it again.<ref>[https://web.archive.org/web/20080628205216/http://www.latimes.com/technology/la-fi-spam11may11001420,1,5168218,full.story Opening Pandora's In-Box].</ref> Now the ban on spam is enforced by the [[Terms of Service]]/[[Acceptable use policy|Acceptable Use Policy]] (ToS/AUP) of internet service providers (ISPs) and peer pressure.

Spam is sent by both otherwise reputable organizations and lesser companies. When spam is sent by otherwise reputable companies it is sometimes referred to as ''Mainsleaze''.<ref name="levine">{{cite web |first=John |last=Levine |website=Internet and e-mail policy and practice |title=The Mainsleaze Blog |url=https://jl.ly/Email/mainsleaze.html |date=October 18, 2011 |access-date=April 1, 2019 |archive-date=April 1, 2019 |archive-url=https://web.archive.org/web/20190401221513/https://jl.ly/Email/mainsleaze.html |url-status=live }}</ref><ref>{{cite web |first=Catherine |last=Jefferson |title=What is Mainsleaze Spam? |website=The Mainsleaze Blog |url=http://mainsleaze.spambouncer.org/ |access-date=April 1, 2019 |archive-date=April 1, 2019 |archive-url=https://web.archive.org/web/20190401221515/http://mainsleaze.spambouncer.org/ |url-status=live }}</ref> Mainsleaze makes up approximately 3% of the spam sent over the internet.<ref name="spambounncer">{{cite web |first=Catherine |last=Jefferson |title=Companies that spam, and ESPs that help them |website=The Mainsleaze Blog |url=http://mainsleaze.spambouncer.org/ |access-date=April 1, 2019 |archive-date=April 1, 2019 |archive-url=https://web.archive.org/web/20190401221515/http://mainsleaze.spambouncer.org/ |url-status=live }}</ref>

===Spamvertised sites===
Many spam emails contain URLs to a website or websites. According to a [[Cyberoam]] report in 2014, there are an average of 54 billion spam messages sent every day. "Pharmaceutical products (Viagra and the like) jumped up 45% from last quarter's analysis, leading this quarter's spam pack. Emails purporting to offer jobs with fast, easy cash come in at number two, accounting for approximately 15% of all spam email. And, rounding off at number three are spam emails about diet products (such as Garcinia gummi-gutta or Garcinia Cambogia), accounting for approximately 1%."<ref name="cyberoam">{{cite press release|title=Q1 2014 Internet Threats Trend Report|publisher=Sophos Cyberoam |url=http://www.cyberoam.com/downloads/ThreatReports/CyberoamCYRENInternetThreats2014April.pdf|access-date=2015-11-01|archive-url=https://web.archive.org/web/20210224144803/http://www.cyberoam.com/downloads/ThreatReports/CyberoamCYRENInternetThreats2014April.pdf|archive-date=24 February 2021}}</ref>

{{Main|Phishing}}

Spam is also a medium for [[fraudster]]s to [[scam]] users into entering personal information on fake Web sites using emails forged to look like they are from banks or other organizations, such as [[PayPal]]. This is known as ''[[phishing]]''. Targeted phishing, where known information about the recipient is used to create forged emails, is known as ''spear-phishing''.<ref name="sophos8"/>

==Spam techniques==

===Appending===
{{Main|Email appending}}

If a marketer has one database containing names, addresses, and telephone numbers of customers, they can pay to have their database matched against an external database containing email addresses. The company then has the means to send email to people who have not requested email, which may include people who have deliberately withheld their email address.<ref>{{cite web|url=http://www.cluelessmailers.org/articles/2008-01-19-gettingitwrong.html |archive-url=https://archive.today/20130414114546/http://www.cluelessmailers.org/articles/2008-01-19-gettingitwrong.html |url-status=dead |archive-date=April 14, 2013 |title=Getting it Wrong: Corporate America Spams the Afterlife |publisher=Clueless Mailers |author=Bob West |date=January 19, 2008 |access-date=2010-09-23 }}</ref>

===Image spam===
{{Main|Image spam}}

[[Image spam]], or image-based spam,<ref name="Image Based spam name">Giorgio Fumera, Ignazio Pillai, Fabio Roli,{{cite journal|url=http://jmlr.csail.mit.edu/papers/v7/fumera06a.html|title=Spam filtering based on the analysis of text information embedded into images|journal=Journal of Machine Learning Research|year=2006|volume=7|issue=98|pages=2699–2720|last1=Fumera|first1=Giorgio|access-date=2013-03-19|archive-date=2015-02-21|archive-url=https://web.archive.org/web/20150221103301/http://jmlr.csail.mit.edu/papers/v7/fumera06a.html|url-status=live}} Journal of Machine Learning Research (special issue on Machine Learning in Computer Security), vol. 7, pp. 2699–2720, 12/2006.</ref><ref name="Image Based spam name 2">Battista Biggio, Giorgio Fumera, Ignazio Pillai, Fabio Roli,{{cite journal|title=A survey and experimental evaluation of image spam filtering techniques| doi=10.1016/j.patrec.2011.03.022 | volume=32|issue=10|journal=Pattern Recognition Letters|pages=1436–1446|year=2011|last1=Biggio|first1=Battista|last2=Fumera|first2=Giorgio|last3=Pillai|first3=Ignazio|last4=Roli|first4=Fabio| bibcode=2011PaReL..32.1436B }} Volume 32, Issue 10, 15 July 2011, Pages 1436–1446, ISSN 0167-8655.</ref> is an obfuscation method by which text of the message is stored as a [[GIF]] or [[JPEG]] image and displayed in the email. This prevents text-based spam filters from detecting and blocking spam messages. Image spam was reportedly used in the mid-2000s to advertise "[[pump and dump]]" stocks.<ref name="techtarget">{{cite news|author=Eric B. Parizo|title=Image spam paints a troubling picture|url=http://searchsecurity.techtarget.com/originalContent/0,289142,sid14_gci1204126,00.html|publisher=Search Security|date=2006-07-26|access-date=2007-01-06|archive-date=2007-02-24|archive-url=https://web.archive.org/web/20070224152029/http://searchsecurity.techtarget.com/originalContent/0%2C289142%2Csid14_gci1204126%2C00.html|url-status=live}}</ref>

Often, image spam contains nonsensical, computer-generated text which simply annoys the reader. However, new technology in some programs tries to read the images by attempting to find text in these images. These programs are not very accurate, and sometimes filter out innocent images of products, such as a box that has words on it.

A newer technique, however, is to use an animated [[GIF]] image that does not contain clear text in its initial frame, or to contort the shapes of letters in the image (as in [[CAPTCHA]]) to avoid detection by [[optical character recognition]] tools.

===Blank spam===
Blank spam is spam lacking a payload advertisement. Often the message body is missing altogether, as well as the subject line. Still, it fits the definition of spam because of its nature as bulk and unsolicited email.<ref>{{cite web|url=http://www.cnet.com/news/dealing-with-blank-spam/|title=Dealing with blank spam|website=CNET|date=September 2, 2009|access-date=August 17, 2015|archive-date=September 23, 2015|archive-url=https://web.archive.org/web/20150923230039/http://www.cnet.com/news/dealing-with-blank-spam/|url-status=live}}</ref>

Blank spam may be originated in different ways, either intentional or unintentionally:
# Blank spam can have been sent in a [[directory harvest attack]], a form of [[dictionary attack]] for gathering valid addresses from an email service provider. Since the goal in such an attack is to use the bounces to separate invalid addresses from the valid ones, spammers may dispense with most elements of the header and the entire message body, and still accomplish their goals.
# Blank spam may also occur when a spammer forgets or otherwise fails to add the payload when they set up the spam run.
# Often blank spam headers appear truncated, suggesting that computer glitches, such as [[software bugs]] or other may have contributed to this problem—from poorly written spam software to malfunctioning relay servers, or any problems that may truncate header lines from the message body.
# Some spam may appear to be blank when in fact it is not. An example of this is the VBS.Davinia.B email worm<ref>{{cite web|url=http://www.symantec.com/security_response/writeup.jsp?docid=2001-020713-3220-99|title=Symantec|publisher=[[Broadcom#Symantec enterprise security|Symantec]]|access-date=2012-12-10|archive-date=2012-11-20|archive-url=https://web.archive.org/web/20121120184413/http://www.symantec.com/security_response/writeup.jsp?docid=2001-020713-3220-99|url-status=dead}}</ref> which propagates through messages that have no subject line and appears blank, when in fact it uses HTML code to download other files.

===Backscatter spam===
{{Main|Backscatter (email)}}{{Unreferenced section|date=July 2025}}
Backscatter is a side-effect of email spam, [[computer viruses|viruses]], and [[computer worm|worms]]. It happens when email servers are misconfigured to send a bogus [[bounce message]] to the [[envelope sender]] when rejecting or quarantining email (rather than simply rejecting the attempt to send the message).

If the sender's address was forged, then the bounce may go to an innocent party. Since these messages were not solicited by the recipients, are substantially similar to each other, and are delivered in bulk quantities, they qualify as unsolicited bulk email or spam. As such, systems that generate email backscatter can end up being listed on various [[DNSBL]]s and be in violation of [[internet service provider]]s' [[Terms of Service]].

==Legal countermeasures==
{{See also|Email spam legislation by country}}
If an individual or organisation can identify harm done to them by spam, and identify who sent it; then they may be able to sue for a [[legal remedy]], e.g. on the basis of [[trespass to chattels]]. A number of large civil settlements have been won in this way,<ref>e.g. [[CompuServe Inc. v. Cyber Promotions, Inc.]], [[School of Visual Arts v. Kuprewicz]]</ref> although others have been mostly unsuccessful in collecting damages.<ref>{{citation|publisher=QC Times|url=http://qctimes.com/news/local/article_7a7b6e00-fba9-5039-bfcb-974b92647deb.html|title=Clinton Internet provider wins $11B suit against spammer|date=4 January 2006 |access-date=2010-12-03|archive-date=2018-06-14|archive-url=https://web.archive.org/web/20180614044637/https://qctimes.com/news/local/article_7a7b6e00-fba9-5039-bfcb-974b92647deb.html|url-status=live}}</ref><ref name="AOL gives up treasure hunt">{{citation|publisher=Boston Herald|url=http://www.bostonherald.com/business/general/view.bg?articleid=1013094&srvc=biz|title=AOL gives up treasure hunt|access-date=2008-01-18|archive-date=2012-08-06|archive-url=https://web.archive.org/web/20120806143424/http://www.bostonherald.com/business/general/view.bg?articleid=1013094&srvc=biz|url-status=live}}</ref>

Criminal prosecution of spammers under fraud or [[computer crime]] statutes is also common, particularly if they illegally accessed other computers to create [[botnets]], or the emails were [[phishing]] or other forms of criminal fraud.<ref>e.g. [[Sanford Wallace]]</ref><ref>{{cite news |title=Bronx man, 'leader' of bank-fraud scam, convicted |url=https://www.lohud.com/story/news/crime/2016/02/26/bronx-man-leader-bank-fraud-scam-convicted/81002016/ |access-date=11 January 2019 |work=Iohud |date=26 February 2016 |archive-date=8 March 2019 |archive-url=https://web.archive.org/web/20190308101301/https://www.lohud.com/story/news/crime/2016/02/26/bronx-man-leader-bank-fraud-scam-convicted/81002016/ |url-status=live }}</ref><ref>{{cite news
|url=http://www.upi.com/Top_News/2009/06/23/Spam-King-pleads-guilty-in-Detroit/UPI-18071245770825/
|title='Spam King' pleads guilty in Detroit
|publisher=UPI
|date=2009-06-23
|access-date=2009-06-23
|archive-date=2009-06-26
|archive-url=https://web.archive.org/web/20090626111014/http://www.upi.com/Top_News/2009/06/23/Spam-King-pleads-guilty-in-Detroit/UPI-18071245770825
|url-status=live
}}</ref><ref>{{cite magazine
|url=https://www.pcworld.com/article/148780/top_spammer_sentenced_to_nearly_four_years.html
|title=Top Spammer Sentenced to Nearly Four Years
|magazine=[[PC World (magazine)|PC World]]
|access-date=2010-10-24
|date=2008-07-22
}}</ref>

Finally, in most countries specific legislation is in place to make certain forms of spamming a criminal offence, as outlined below:

===European Union===
Article 13 of the [[European Union]] [[Directive on Privacy and Electronic Communications]] (2002/58/EC) provides that the [[European Union|EU]] member states shall take appropriate measures to ensure that unsolicited communications for the purposes of direct marketing are not allowed either without the consent of the subscribers concerned or in respect of subscribers who do not wish to receive these communications, the choice between these options to be determined by national legislation.<ref>{{Citation |title=Directive 2002/58/EC of the European Parliament and of the Council of 12 July 2002 concerning the processing of personal data and the protection of privacy in the electronic communications sector (Directive on privacy and electronic communications) |date=2002-07-12 |volume=201 |url=https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex:32002L0058 |access-date=2024-12-15 |language=en}}</ref>

===United Kingdom===
In the United Kingdom, for example, unsolicited emails cannot be sent to an individual subscriber unless prior permission has been obtained or unless there is a pre-existing commercial relationship between the parties.<ref>[[Privacy and Electronic Communications (EC Directive) Regulations 2003]]</ref><ref>{{citation|publisher=ICO|url=http://ico.org.uk/enforcement|title=Enforcement|access-date=2014-01-16|archive-date=2014-01-16|archive-url=https://web.archive.org/web/20140116204857/http://ico.org.uk/enforcement|url-status=live}}</ref>

===Canada===
The 2010 [[Fighting Internet and Wireless Spam Act]] (which took effect in 2014)<ref>{{citation|place=CA|publisher=GC|url=http://www2.parl.gc.ca/HousePublications/Publication.aspx?Docid=4547728&&File=50|title=Fighting Internet and Wireless Spam Act}}</ref> is Canadian legislation meant to fight spam.<ref>{{citation|publisher=Circle ID|url=http://www.circleid.com/posts/20101215_canada_anti_spam_bill_c_28_is_the_law_of_the_land|title=Canada's Anti-spam Bill C-28 is the Law of the Land|date=2010-12-15|access-date=2011-03-14|archive-date=2011-03-24|archive-url=https://web.archive.org/web/20110324003851/http://www.circleid.com/posts/20101215_canada_anti_spam_bill_c_28_is_the_law_of_the_land|url-status=live}}</ref>

===Australia===
The [[Spam Act 2003]], which covers some types of email and phone spam.<ref>{{cite web|url=http://www.austlii.edu.au/au/legis/cth/consol_act/sa200366/sch2.html|title=Commonwealth Consolidated Acts: Spam Act 2003 – Schedule 2|publisher=AustLII, Faculty of Law, University of Technology|location=Sydney, AU|access-date=2010-09-23|archive-date=2011-05-18|archive-url=https://web.archive.org/web/20110518153309/http://www.austlii.edu.au/au/legis/cth/consol_act/sa200366/sch2.html|url-status=live}}</ref> Penalties are up to 10,000 [[penalty units]], or 2,000 penalty units for a person other than a body corporate.

===United States===
In the United States, many states enacted anti-spam laws during the late 1990s and early 2000s. All of these were subsequently superseded by the [[CAN-SPAM Act of 2003]],<ref>But see, e.g., [https://scholar.google.com/scholar_case?case=9837985979753739551&q=hypertouch+v+valueclick&hl=en&as_sdt=2,5&as_vis=1  Hypertouch v. ValueClick, Inc. et al., Cal.App.4th] {{Webarchive|url=https://web.archive.org/web/20170415075651/http://scholar.google.com/scholar_case?case=9837985979753739551&q=hypertouch+v+valueclick&hl=en&as_sdt=2,5&as_vis=1 |date=2017-04-15 }} (Google Scholar: January 18, 2011)</ref> which was in many cases less restrictive. CAN-SPAM also preempted any further state legislation, but it left related laws not specific to e-mail intact.<ref>{{citation
 | title = PUBLIC LAW 108-187--DEC. 16, 2003 117 STAT. 2699
 | section = SEC. 8. EFFECT ON OTHER LAWS
 | quote = (2) STATE LAW NOT SPECIFIC TO ELECTRONIC ~ZL.--This Act shall not be construed to preempt the applicability of(A) State laws that are not specific to electronic mail, including State trespass, contract, or tot~ law; or (B) other State laws to the extent that those laws relate to acts of fraud or computer crime.
 | url = https://www.ftc.gov/sites/default/files/documents/cases/2007/11/canspam.pdf
 | publisher = FTC
 }}</ref> Courts have ruled that spam can constitute, for example, trespass to chattels.<ref>{{citation
 | title = "Trespass to Chattels" Finds New Life In Battle Against Spam
 | author1 = Daniel J. Schwartz
 | author2 = Joseph F. Marinelli
 | publisher = Association of Corporate Counsel
 | date = September 2004
 | url = https://jenner.com/system/assets/publications/7997/original/Trespass_to_Chattels.pdf?1324590104
 | access-date = 2019-02-11
 | archive-date = 2019-02-12
 | archive-url = https://web.archive.org/web/20190212011857/https://jenner.com/system/assets/publications/7997/original/Trespass_to_Chattels.pdf?1324590104
 | url-status = live
 }}</ref>

Bulk commercial email does not violate CAN-SPAM, provided that it meets certain criteria, such as a truthful subject line, no forged information in the headers. If it fails to comply with any of these requirements it is illegal. Those opposing spam greeted the new law with dismay and disappointment, almost immediately dubbing it the "You Can Spam" Act.<ref>{{cite web |url=http://weblog.infoworld.com/gripeline/2003/11/24.html |title=The 'Yes, You Can Spam' Act of 2003 |work=The Gripe Line Weblog |first=Ed |last=Foster |date=November 24, 2003 |access-date=2007-03-09 |url-status=dead |archive-url=https://web.archive.org/web/20070406195036/http://weblog.infoworld.com/gripeline/2003/11/24.html |archive-date=2007-04-06 }}</ref><ref>{{cite web|url=http://www.spamhaus.org/news.lasso?article=150|title=United States set to Legalize Spamming on January 1, 2004|publisher=Spamhaus.org|access-date=7 January 2015|archive-date=12 January 2012|archive-url=https://web.archive.org/web/20120112121235/http://www.spamhaus.org/news.lasso?article=150|url-status=live}}</ref>

In practice, it had a little positive impact. In 2004, less than one percent of spam complied with CAN-SPAM,<ref>{{citation|publisher=PC World|url=http://www.pcworld.com/article/id,114287-page,1/article.html|title=Is the CAN-SPAM Law Working?|access-date=2008-03-21|archive-date=2008-03-15|archive-url=https://web.archive.org/web/20080315222220/http://www.pcworld.com/article/id,114287-page,1/article.html|url-status=live}}</ref> although a 2005 review by the Federal Trade Commission claimed that the amount of sexually explicit spam had significantly decreased since 2003 and the total volume had begun to level off.<ref>{{citation|publisher=FTC |place=USA |url=http://www.ftc.gov/reports/canspam05/051220canspamrpt.pdf |title=Effectiveness and Enforcement of the CAN-SPAM Act |url-status=dead |archive-url=https://web.archive.org/web/20060110053628/http://www.ftc.gov/reports/canspam05/051220canspamrpt.pdf |archive-date=January 10, 2006 }}</ref> Many other observers viewed it as having failed,<ref>{{citation|author=Ken Fisher|publisher=Ars Technica|date=December 2005|url=https://arstechnica.com/old/content/2005/12/5810.ars|title=US FTC says CAN-SPAM works|access-date=2017-06-14|archive-date=2011-09-11|archive-url=https://web.archive.org/web/20110911161733/http://arstechnica.com/old/content/2005/12/5810.ars|url-status=live}}</ref><ref>{{citation |publisher=SC Magazine |place=USA |url=http://www.scmagazineus.com/six-years-later-can-spam-act-leaves-spam-problem-unresolved/article/163857 |title=Six years later, Can Spam act leaves spam problem unresolved |url-status=dead |archive-url=https://web.archive.org/web/20100903202146/http://www.scmagazineus.com/six-years-later-can-spam-act-leaves-spam-problem-unresolved/article/163857/ |archive-date=2010-09-03 }}</ref> although there have been several high-profile prosecutions.<ref>e.g. [[Oleg Nikolaenko]]</ref><ref>{{cite news |title=Los Angeles Man, First American Convicted Under Anti-Spam Law, Faces Years in Prison |url=https://www.foxnews.com/story/los-angeles-man-first-american-convicted-under-anti-spam-law-faces-years-in-prison |access-date=9 January 2019 |agency=AP |date=17 January 2007 |archive-date=10 January 2019 |archive-url=https://web.archive.org/web/20190110013739/https://www.foxnews.com/story/los-angeles-man-first-american-convicted-under-anti-spam-law-faces-years-in-prison |url-status=live }}</ref>

==Deception and fraud==
Spammers may engage in deliberate [[fraud]] to send out their messages. Spammers often use false names, addresses, phone numbers, and other contact information to set up "disposable" accounts at various Internet service providers. They also often use falsified or stolen [[credit card]] numbers to pay for these accounts. This allows them to move quickly from one account to the next as the host ISPs discover and shut down each one.

Senders may go to great lengths to conceal the origin of their messages. Large companies may hire another firm to send their messages so that complaints or blocking of email falls on a third party. Others engage in [[Spoofing attack|spoof]]ing of email addresses (much easier than [[IP address spoofing]]). The email protocol ([[SMTP]]) has no authentication by default, so the spammer can pretend to originate a message apparently from any email address. To prevent this, some ISPs and domains require the use of [[SMTP-AUTH]], allowing positive identification of the specific account from which an email originates.

Senders cannot completely spoof [[spam email delivery|email delivery]] chains (the 'Received' header), since the receiving mailserver records the actual connection from the last mailserver's IP address. To counter this, some spammers forge additional delivery headers to make it appear as if the email had previously traversed many legitimate servers.

Spoofing can have serious consequences for legitimate email users. Not only can their email inboxes get clogged up with "undeliverable" emails in addition to volumes of spam, but they can mistakenly be identified as a spammer. Not only may they receive irate email from spam victims, but (if spam victims report the email address owner to the ISP, for example) a naïve ISP may terminate their service for spamming.

==Theft of service==
Spammers frequently seek out and make use of vulnerable third-party systems such as [[open mail relay]]s and open [[proxy server]]s. SMTP forwards mail from one server to another—mail servers that ISPs run commonly require some form of [[authentication]] to ensure that the user is a customer of that ISP.

Increasingly, spammers use networks of malware-infected PCs ([[Zombie computer|zombies]]) to send their spam. [[Zombie computer|Zombie]] networks are also known as [[botnet]]s (such zombifying malware is known as a ''bot'', short for [[robot]]). In June 2006, an estimated 80 percent of email spam was sent by zombie PCs, an increase of 30 percent from the prior year. An estimated 55&nbsp;billion email spam were sent each day in June 2006, an increase of 25&nbsp;billion per day from June 2005.<ref name="ironport">{{cite press release
|title=Spammers Continue Innovation: IronPort Study Shows Image-based Spam, Hit & Run, and Increased Volumes Latest Threat to Your Inbox|publisher=IronPort Systems|date=2006-06-28|url=http://www.ironport.com/company/ironport_pr_2006-06-28.html|access-date=2007-01-05 }}</ref>

For the first quarter of 2010, an estimated 305,000 newly activated zombie PCs were brought online each day for malicious activity. This number is slightly lower than the 312,000 of the fourth quarter of 2009.<ref name="commtouch">{{cite press release|title=Q1 2010 Internet Threats Trend Report|publisher=Commtouch Software Ltd.|url=http://www.commtouch.com/download/1679|format=PDF|access-date=2010-09-23}}</ref>

Brazil produced the most zombies in the first quarter of 2010. Brazil was the source of 20 percent of all zombies, which is down from 14 percent from the fourth quarter of 2009. India had 10 percent, with Vietnam at 8 percent, and the Russian Federation at 7 percent.<ref name="commtouch"/>

===Side effects===
{{Original research|date=October 2015}}To combat the problems posed by botnets, open relays, and proxy servers, many email server administrators pre-emptively block dynamic IP ranges and impose stringent requirements on other servers wishing to deliver mail. [[Forward-confirmed reverse DNS]] must be correctly set for the outgoing mail server and large swaths of IP addresses are blocked, sometimes pre-emptively, to prevent spam. These measures can pose problems for those wanting to run a small email server off an inexpensive domestic connection. Blacklisting of IP ranges due to spam emanating from them also causes problems for legitimate email servers in the same IP range.

==Statistics and estimates==
The total volume of email spam has been consistently growing, but in 2011 the trend seemed to reverse.<ref>{{cite web|author=Charlie White|url=http://mashable.com/2011/07/04/spam-decreased-82percent|title=Spam Decreased 82.22% Over The Past Year|publisher=Mashable.com|date=2011-07-04|access-date=2012-12-10|archive-date=2012-12-13|archive-url=https://web.archive.org/web/20121213162907/http://mashable.com/2011/07/04/spam-decreased-82percent/|url-status=live}}</ref><ref>{{cite web|url=http://www.symanteccloud.com/globalthreats/charts/spam_monthly|title=Spam|language=nl|publisher=Symantec.cloud|access-date=2012-12-10|archive-date=2012-12-14|archive-url=https://web.archive.org/web/20121214123038/http://www.symanteccloud.com/globalthreats/charts/spam_monthly|url-status=live}}</ref> The amount of spam that users see in their mailboxes is only a portion of total spam sent, since spammers' lists often contain a large percentage of invalid addresses and many spam filters simply delete or reject "obvious spam".

The first known spam email, advertising a DEC product presentation, was sent in 1978 by Gary Thuerk to 600 addresses, the total number of users on [[ARPANET]] was 2600 at the time though software limitations meant only slightly more than half of the intended recipients actually received it.<ref name="templetonsreact">{{cite web|url=http://www.templetons.com/brad/spamreact.html|title=Reaction to the DEC Spam of 1978|author=Brad Templeton|author-link=Brad Templeton|access-date=2007-01-21|date=8 March 2005<!-- 08:30:08 GMT-->|publisher=Brad Templeton|archive-date=2013-07-30|archive-url=https://web.archive.org/web/20130730073440/http://www.templetons.com/brad/spamreact.html|url-status=live}}</ref> As of August 2010, the number of spam messages sent per day was estimated to be around 200&nbsp;billion.<ref name="TG">{{cite news|url=https://www.theguardian.com/technology/2011/jan/10/email-spam-record-activity|title=Email spam level bounces back after record low|author=Josh Halliday|work=[[guardian.co.uk]]|date=10 January 2011|access-date=2011-01-11|archive-date=2015-04-03|archive-url=https://web.archive.org/web/20150403131922/http://www.theguardian.com/technology/2011/jan/10/email-spam-record-activity|url-status=live}}</ref> More than 97% of all emails sent over the Internet in 2008 were unwanted, according to a [[Microsoft]] security report.<ref>{{cite news|last=Waters|first=Darren|url=https://news.bbc.co.uk/1/hi/technology/7988579.stm|title=Spam overwhelms email messages|work=BBC News|date=2009-04-08|access-date=2012-12-10|archive-date=2012-12-02|archive-url=https://web.archive.org/web/20121202172638/http://news.bbc.co.uk/2/hi/technology/7988579.stm|url-status=live}}</ref> MAAWG estimates that 85% of incoming mail is "abusive email", as of the second half of 2007. The sample size for the MAAWG's study was over 100 million mailboxes.<ref name="maawgpdf7">{{citation|title=Email Metrics Program: The Network Operators' Perspective |version=Report No.&nbsp;7 – Third and Fourth quarters 2007 |journal=Messaging Anti-Abuse Working Group |date=April 2008 |access-date=2008-05-08 |url=http://www.maawg.org/about/MAAWG_2007-Q3-4_Metrics_Report.pdf |url-status=dead |archive-url=https://web.archive.org/web/20080724000732/http://www.maawg.org/about/MAAWG_2007-Q3-4_Metrics_Report.pdf |archive-date=2008-07-24 }}</ref><ref name="maawgpdf1">{{citation|title=Email Metrics Program: The Network Operators' Perspective|version=Report No.&nbsp;1 – 4th quarter 2005 Report|publisher=Messaging Anti-Abuse Working Group|date=March 2006|access-date=2007-01-06|url=http://www.maawg.org/about/FINAL_4Q2005_Metrics_Report.pdf|archive-url=https://web.archive.org/web/20061208004106/http://www.maawg.org/about/FINAL_4Q2005_Metrics_Report.pdf|archive-date=December 8, 2006}}</ref><ref name="maawgpdf2">{{citation|title=Email Metrics Program: The Network Operators' Perspective |version=Report No.&nbsp;2 – 1st quarter 2006 |publisher=Messaging Anti-Abuse Working Group |date=June 2006 |access-date=2007-01-06 |url=http://www.maawg.org/about/FINAL_1Q2006_Metrics_Report.pdf |archive-url=https://web.archive.org/web/20060924221430/http://www.maawg.org/about/FINAL_1Q2006_Metrics_Report.pdf |archive-date=2006-09-24 |url-status=dead }}</ref> In 2018 with growing affiliation networks & email frauds worldwide about 90% of global email traffic is spam as per IPwarmup.com study, which also effects legitimate email senders to achieve inbox delivery.<ref name="IPWarmup.com - Study">{{cite web |title=IPWarmup.com - Study |url=https://ipwarmup.com/ |access-date=2018-10-21 |archive-date=2018-10-21 |archive-url=https://web.archive.org/web/20181021232327/https://ipwarmup.com/ |url-status=live }}</ref>

A 2010 survey of US and European email users showed that 46% of the respondents had opened spam messages, although only 11% had clicked on a link.<ref>{{cite web|url=http://www.maawg.org/sites/maawg/files/news/2010_MAAWG-Consumer_Survey.pdf|title=2010 MAAWG Email Security Awareness and Usage Report, Messing Anti-Abuse Working Group/Ipsos Public Affairs|access-date=2012-12-10|archive-date=2013-03-08|archive-url=https://web.archive.org/web/20130308032827/http://www.maawg.org/sites/maawg/files/news/2010_MAAWG-Consumer_Survey.pdf|url-status=live}}</ref>

In 2023, 160 billion spam messages were sent every day. The US sends the most spam messages (8 billion per day), followed by China (7.6 billion per day). The main topic is delivery service messages (in the US in the first half of 2023 more than 1.1 billion).<ref>{{Cite web |last=Ellis |first=Cai |date=2023-10-19 |title=Spam Statistics 2025: Survey on Junk Email, AI Scams & Phishing |url=https://www.emailtooltester.com/en/blog/spam-statistics/ |access-date=2025-02-26 |website=EmailTooltester.com |language=en-US}}</ref>

===Highest amount of spam received===
According to [[Steve Ballmer]] in 2004, Microsoft founder [[Bill Gates]] receives four million emails per year, most of them spam.<ref name="bbc">{{cite news|author=Staff|title=Bill Gates 'most spammed person'|url=https://news.bbc.co.uk/2/hi/business/4023667.stm|work=BBC News|date=18 November 2004|access-date=2010-09-23|archive-date=2011-05-02|archive-url=https://web.archive.org/web/20110502152032/http://news.bbc.co.uk/2/hi/business/4023667.stm|url-status=live}}</ref> This was originally incorrectly reported as "per day".<ref name="acme1">{{cite news|author=Mike Wendland|title=Ballmer checks out my spam problem|url=http://www.acme.com/mail_filtering/article_2.html|publisher=ACME Laboratories republication of article appearing in Detroit Free Press|date=December 2, 2004|access-date=2010-09-23|archive-date=2010-09-17|archive-url=https://web.archive.org/web/20100917102049/http://acme.com/mail_filtering/article_2.html|url-status=live}} ''the date provided is for the original article; the date of revision for the republication is 8 June 2005; verification that content of the republication is the same as the original article is pending''.</ref>

At the same time [[Jef Poskanzer]], owner of the domain name acme.com, was receiving over one million spam emails per day.<ref name="acme2">{{cite web|url=http://www.acme.com/mail_filtering|title=Mail Filtering|author=Jef Poskanzer|date=2006-05-15|publisher=ACME Laboratories|access-date=2010-09-23|archive-date=2010-09-17|archive-url=https://web.archive.org/web/20100917033755/http://acme.com/mail_filtering/|url-status=live}}</ref>

===Cost of spam===
A 2004 survey estimated that lost productivity costs Internet users in the United States $21.58&nbsp;billion annually, while another reported the cost at $17&nbsp;billion, up from $11&nbsp;billion in 2003. In 2004, the worldwide productivity cost of spam has been estimated to be $50&nbsp;billion in 2005.<ref>{{Cite web |url=http://www.informationweek.com/story/showArticle.jhtml?articleID=59300834 |title=Spam Costs Billions |access-date=2008-01-18 |archive-date=2007-09-04 |archive-url=https://web.archive.org/web/20070904040044/http://www.informationweek.com/story/showArticle.jhtml?articleID=59300834 |url-status=live }}</ref>

In 2023, 56.2 million people lost a total of $25.4 billion, with victims losing an average of $452. The amount lost and the number of victims has increased significantly over the past decade, with 18 million people losing a total of $8.6 billion in 2014.<ref>{{Cite web |last=Ellis |first=Cai |date=2023-10-19 |title=Spam Statistics 2025: Survey on Junk Email, AI Scams & Phishing |url=https://www.emailtooltester.com/en/blog/spam-statistics/ |access-date=2025-02-26 |website=EmailTooltester.com |language=en-US}}</ref>

===Origin of spam===
{{Bar chart
| title    = E-mail spam relayed by country in Q2 2007 (% of total)<ref>{{Cite press release|url=https://www.sophos.com/en-us/press-office/press-releases/2007/07/dirtydozjul07.aspx|title=Sophos reveals "dirty dozen" spam-relaying countries|author=Sophos|access-date=2020-04-13}}</ref>
| label_type  = Country
| data_type   = Percentage
| bar_width   = 15
| width_units = em
| data_max = 25
| float = right
| label1   = United States
| data1    = 19.6
| label2   = EU (Top 5)
| data2    = 17.9
| label3   = China (+ Hong Kong)
| data3    = 8.4
| label4   = South Korea
| data4    = 6.5
| label5   = Poland
| data5    = 4.8
| label6   = Germany
| data6    = 4.2
| label7   = Brazil
| data7    = 4.1
| label8   = France
| data8    = 3.3
| label9   = Russia
| data9    = 3.1
| label10  = Turkey
| data10   = 2.9
| label11  = United Kingdom
| data11   = 2.8
| label12  = Italy
| data12   = 2.8
| label13  = India
| data13   = 2.5
}}
Because of the international nature of spam, the spammer, the hijacked spam-sending computer, the spamvertised server, and the user target of the spam are all often located in different countries. As much as 80% of spam received by Internet users in [[North America]] and [[Europe]] can be traced to fewer than 200 spammers.<ref>[http://www.spamhaus.org/rokso/index.lasso Register of Known Spam Operations] {{Webarchive|url=https://web.archive.org/web/20070612174611/http://www.spamhaus.org/rokso/index.lasso |date=2007-06-12 }} ([[The Spamhaus Project|ROKSO]]).</ref>

'''In terms of volume of spam:''' According to [[Sophos]], the major sources of spam in the fourth quarter of 2008 (October to December) were:{{Unreliable source?|date=December 2009}}<ref name="sophos8">{{cite press release|title=Only one in 28 emails legitimate, Sophos report reveals rising tide of spam in April–June 2008|publisher=Sophos|date=2008-07-15|access-date=2008-10-12|url=http://www.sophos.com/pressoffice/news/articles/2008/07/dirtydozjul08.html }}</ref><ref name="sophos1">{{cite press release|title=Sophos reveals 'Dirty Dozen' spam producing countries, August 2004|publisher=Sophos|date=2004-08-24|access-date=2007-01-06|url=http://www.sophos.com/pressoffice/news/articles/2004/08/sa_dirtydozenaug04.html }}</ref><ref name="sophos2">{{cite press release|title=Sophos reveals 'dirty dozen' spam relaying countries|publisher=Sophos|date=2006-07-24|access-date=2007-01-06|url=http://www.sophos.com/pressoffice/news/articles/2006/07/dirtydozjul06.html}}</ref><ref name="sophos3">{{cite press release|title=Sophos research reveals dirty dozen spam-relaying nations|publisher=Sophos|date=2007-04-11|access-date=2007-06-15|url=http://www.sophos.com/pressoffice/news/articles/2007/04/dirtydozapr07.html}}</ref><ref name="sophos4">{{cite press release|title=Sophos reveals 'Dirty Dozen' spam producing countries, July 2007|publisher=Sophos|date=2007-07-18|access-date=2007-07-24|url=http://www.sophos.com/pressoffice/news/articles/2007/07/dirtydozjul07.html }}</ref><ref name="sophos5">{{cite press release|title=Sophos reveals 'Dirty Dozen' spam producing countries for Q3 2007|publisher=Sophos|date=2007-10-24|access-date=2007-11-09|url=http://www.sophos.com/pressoffice/news/articles/2007/10/dirtydozoct07.html }}</ref><ref name="sophos6">{{cite press release|title=Sophos details dirty dozen spam-relaying countries for Q4 2007|publisher=Sophos|date=2008-02-11|access-date=2008-02-12|url=http://www.sophos.com/pressoffice/news/articles/2008/02/dirtydozfeb08.html }}</ref><ref name="sophos7">{{cite press release|title=Sophos details dirty dozen spam-relaying countries for Q1 2008|publisher=Sophos|date=2008-04-14|access-date=2008-06-07|url=http://www.sophos.com/pressoffice/news/articles/2008/04/dirtydozapr08.html }}</ref><ref name="sophos9">{{cite press release|title=Eight times more malicious email attachments spammed out in Q3 2008|publisher=Sophos|date=2008-10-27|access-date=2008-11-02|url=http://www.sophos.com/pressoffice/news/articles/2008/10/spamreport.html }}</ref><ref name="sophos10">{{cite press release|title=Spammers defy Bill Gates's death-of-spam prophecy|publisher=Sophos|date=2009-01-22|access-date=2009-01-22|url=http://www.sophos.com/pressoffice/news/articles/2009/01/dirty-dozen.html }}</ref>
* The United States (the origin of 19.8% of spam messages, up from 18.9% in Q3)
* China (9.9%, up from 5.4%)
* Russia (6.4%, down from 8.3%)
* Brazil (6.3%, up from 4.5%)
* Turkey (4.4%, down from 8.2%)

When grouped by continents, spam comes mostly from:
* Asia (37.8%, down from 39.8%)
* North America (23.6%, up from 21.8%)
* Europe (23.4%, down from 23.9%)
* South America (12.9%, down from 13.2%)

'''In terms of number of IP addresses:''' the [[Spamhaus Project]] ranks the top three as the United States, China, and Russia,<ref name="spaumhaus1">{{cite web|url=http://www.spamhaus.org/statistics/countries.lasso|title=Spamhaus Statistics: The Top 10|access-date=2007-01-06|type=dynamic report|work=Spamhaus Blocklist (SBL) database|publisher=The Spamhaus Project Ltd.|archive-date=2007-01-10|archive-url=https://web.archive.org/web/20070110202452/http://www.spamhaus.org/statistics/countries.lasso|url-status=live}}</ref> followed by Japan, Canada, and South Korea.

'''In terms of networks:''' {{As of|2021|12|13}}, the three networks hosting the most spammers are [[China Telecommunications Corporation|ChinaNet]], [[Amazon Web Services|Amazon]], and [[Airtel|Airtel India]].<ref>{{Cite web |url=https://www.spamhaus.org/statistics/botnet-isp |title=The Spamhaus Project - the Top 10 Worst Botnet Countries |access-date=2021-12-13 |archive-date=2021-10-22 |archive-url=https://web.archive.org/web/20211022120417/https://www.spamhaus.org/statistics/botnet-isp/ |url-status=dead }}</ref>

==Anti-spam techniques==
{{Main|Anti-spam techniques}}
[[File:Spam.png|thumb|Mozilla Thunderbird alerting a user that an email could be spam]]
The U.S. Department of Energy [[Computer Incident Advisory Capability]] (CIAC) has provided specific countermeasures against email spamming.<ref name="ciac">{{cite web |url=http://www.ciac.org/ciac/bulletins/i-005c.shtml |title=I-005c: E-Mail Spamming countermeasures: Detection and prevention of E-Mail spamming |access-date=2007-01-06 |author=Shawn Hernan |author2=James R. Cutler |author3=David Harris |date=1997-11-25 |work=Computer Incident Advisory Capability Information Bulletins |publisher=United States Department of Energy |url-status=usurped |archive-url=https://web.archive.org/web/20070104065059/http://www.ciac.org/ciac/bulletins/i-005c.shtml |archive-date=2007-01-04 }}</ref>

Some popular methods for filtering and refusing spam include [[email filtering]] based on the content of the email, DNS-based blackhole lists ([[DNSBL]]), [[Greylisting (email)|greylisting]], [[spamtrap]]s, enforcing technical requirements of email ([[Simple Mail Transfer Protocol|SMTP]]), checksumming systems to detect bulk email, and by putting some sort of cost on the sender via a [[proof-of-work system]] or a [[micropayment]]. Each method has strengths and weaknesses and each is controversial because of its weaknesses. For example, one company's offer to "[remove] some spamtrap and honeypot addresses" from email lists defeats the ability for those methods to identify spammers.

[[Anti-spam techniques#Outbound spam protection|Outbound spam protection]] combines many of the techniques to scan messages exiting out of a service provider's network, identify spam, and taking action such as blocking the message or shutting off the source of the message.

[[Email authentication]] to prevent "From:" address spoofing became popular in the 2010s.

=== Collateral damage ===

Measures to protect against spam can cause collateral damage. This includes:
* The measures may consume resources, both in the server and on the network.
* When legitimate messages are rejected, the sender needs to contact the recipient out of channel.
* When legitimate messages are relegated to a spam folder, the sender is not notified of this.
* If a recipient periodically checks their spam folder, that will cost them time and if there is a lot of spam it is easy to overlook the few legitimate messages.

==Methods of spammers==
{{unreferenced section|date=November 2011}}

===Gathering of addresses===
{{Main|Email address harvesting}}

In order to send spam, spammers need to obtain the email addresses of the intended recipients. To this end, both spammers themselves and ''list merchants'' gather huge lists of potential email addresses. Since spam is, by definition, unsolicited, this ''address harvesting'' is done without the consent (and sometimes against the expressed will) of the address owners. A single spam run may target tens of millions of possible addresses – many of which are invalid, malformed, or undeliverable.

===Obfuscating message content===
Many spam-filtering techniques work by searching for patterns in the headers or bodies of messages. For instance, a user may decide that all email they receive with the word "[[Sildenafil|Viagra]]" in the subject line is spam, and instruct their mail program to automatically delete all such messages. To defeat such filters, the spammer may intentionally misspell commonly filtered words or insert other characters, often in a style similar to [[leetspeak]], as in the following examples: {{mono|V1agra}}, {{mono|Via'gra}}, {{mono|Vi@graa}}, {{mono|vi*gra}}, {{mono|\/iagra}}. This also allows for many different ways to express a given word, making identifying them all more difficult for filter software.

The principle of this method is to leave the word readable to humans (who can easily recognize the intended word for such misspellings), but not likely to be recognized by a computer program. This is only somewhat effective, because modern filter patterns have been designed to recognize blacklisted terms in the various iterations of misspelling. Other filters target the actual obfuscation methods, such as the non-standard use of punctuation or numerals into unusual places. Similarly, HTML-based email gives the spammer more tools to obfuscate text. Inserting HTML comments between letters can foil some filters. Another common ploy involves presenting the text as an image, which is either sent along or loaded from a remote server.

===Defeating Bayesian filters===
As [[Bayesian spam filtering|Bayesian filtering]] has become popular as a spam-filtering technique, spammers have started using methods to weaken it. To a rough approximation, Bayesian filters rely on word probabilities. If a message contains many words that are used only in spam, and few that are never used in spam, it is likely to be spam. To weaken Bayesian filters, some spammers, alongside the sales pitch, now include lines of irrelevant, random words, in a technique known as [[Bayesian poisoning]]. More broadly machine learning can be used to identify and filter spam.<ref>{{cite journal |last1=Dada |first1=Emmanuel Gbenga |title=Machine learning for email spam filtering: review, approaches and open research problems |journal=Heliyon |date=2019 |volume=5 |issue=6 |url=https://www.sciencedirect.com/science/article/pii/S2405844018353404}}</ref><ref>{{Cite journal |last=Blanzieri |first=Enrico |date=January 2008 |title=A Survey of Learning-Based Techniques of Email Spam Filtering |url=http://eprints.biblio.unitn.it/1070/1/056.pdf |journal=University of Trento Technical Reports |issue=Technical Report # DIT-06-056}}</ref> There is a game of escalation between spammers and anti-spam identification and filtering systems where spammers adjust to attempt to evade new identification and filtering techniques.

===Spam-support services===
A number of other online activities and business practices are considered by anti-spam activists to be connected to spamming. These are sometimes termed '''spam-support services''': business services, other than the actual sending of spam itself, which permit the spammer to continue operating. Spam-support services can include processing orders for goods advertised in spam, hosting Web sites or [[Domain Name System|DNS]] records referenced in spam messages, or a number of specific services as follows:

Some Internet hosting firms advertise '''bulk-friendly''' or '''bulletproof hosting'''. This means that, unlike most ISPs, they will not terminate a customer for spamming. These hosting firms operate as clients of larger ISPs, and many have eventually been taken offline by these larger ISPs as a result of complaints regarding spam activity. Thus, while a firm may advertise bulletproof hosting, it is ultimately unable to deliver without the connivance of its upstream ISP. However, some spammers have managed to get what is called a [[pink contract]] (see below) – a contract with the ISP that allows them to spam without being disconnected.

A few companies produce '''[[spamware]]''', or software designed for spammers. Spamware varies widely, but may include the ability to import thousands of addresses, to generate random addresses, to insert fraudulent headers into messages, to use dozens or hundreds of mail servers simultaneously, and to make use of open relays. The sale of spamware is illegal in eight U.S. states.<ref name="spamsights1">{{cite web|url=http://www.spamsights.org/|title=Spamware vendor list|publisher=Spam Sights|access-date=2007-01-06|date=2005-07-08|author=Sapient Fridge|archive-date=2014-08-11|archive-url=https://web.archive.org/web/20140811004652/http://www.spamsights.org/|url-status=live}}</ref><ref name="spaumhaus3">{{cite web|url=http://www.spamhaus.org/sbl/policy.html|title=SBL Policy & Listing Criteria|access-date=2007-01-06|date=2006-12-22|publisher=The Spamhaus Project|archive-date=2007-01-05|archive-url=https://web.archive.org/web/20070105194103/http://www.spamhaus.org/SBL/policy.html|url-status=live}} ''original location was at {{citation|url=http://www.spamhaus.org/sbl/sbl-rationale.html|title=SBL rationale|access-date=2004-10-12|archive-date=2004-10-10|archive-url=https://web.archive.org/web/20041010234532/http://www.spamhaus.org/sbl/sbl-rationale.html|url-status=live}}; the referenced page is an auto-redirect target from the original location''</ref><ref name="bitpipe">{{cite web|title=Spamware – Email Address Harvesting Tools and Anonymous Bulk Emailing Software|publisher=MX Logic (abstract hosted by Bit Pipe)|date=2004-10-01|url=http://www.bitpipe.com/detail/RES/1097086148_134.html|access-date=2007-01-06|archive-date=2007-01-23|archive-url=https://web.archive.org/web/20070123082102/http://www.bitpipe.com/detail/RES/1097086148_134.html|url-status=dead}} ''the link here is to an abstract of a white paper; registration with the authoring organization is required to obtain the full white paper''.</ref>

So-called '''millions CDs''' are commonly advertised in spam. These are [[CD-ROM]]s purportedly containing lists of email addresses, for use in sending spam to these addresses. Such lists are also sold directly online, frequently with the false claim that the owners of the listed addresses have requested (or "opted in") to be included. Such lists often contain invalid addresses. In recent years, these have fallen almost entirely out of use due to the low quality email addresses available on them, and because some email lists exceed 20GB in size. The [[CD-ROM#Capacity|amount you can fit on a CD]] is no longer substantial.

A number of [[DNSBL|DNS blacklists]] (DNSBLs), including the MAPS RBL, Spamhaus SBL, SORBS and SPEWS, target the providers of spam-support services as well as spammers. DNSBLs blacklist IPs or ranges of IPs to persuade ISPs to terminate services with known customers who are spammers or resell to spammers.

==Related vocabulary==
;Unsolicited bulk email (UBE)
:A synonym for email spam.
;Unsolicited commercial email (UCE)
:Spam promoting a commercial service or product. This is the most common type of spam, but it excludes spams that are hoaxes (e.g. virus warnings), political advocacy, religious messages, and [[chain letter]]s sent by a person to many other people. The term UCE may be most common in the USA.<ref name="caube">{{cite web |url=http://www.caube.org.au/whatis.htm |title=Definitions of Words We Use |access-date=2007-01-06 |publisher=Coalition Against Unsolicited Bulk Email, Australia |url-status=dead |archive-url=https://web.archive.org/web/20070106050512/http://www.caube.org.au/whatis.htm |archive-date=2007-01-06 }}</ref>
;Pink contract
:A [[pink contract]] is a service contract offered by an ISP which offers bulk email service to spamming clients, in violation of that ISP's publicly posted acceptable use policy.
;Spamvertising
:[[Spamvertising]] is advertising through the medium of spam.
;Opt-in, confirmed opt-in, double opt-in, opt-out
:[[opt in email|Opt-in, confirmed opt-in, double opt-in, opt-out]] refers to whether the people on a mailing list are given the option to be put in, or taken out, of the list. Confirmation (and "double", in marketing speak) refers to an email address transmitted e.g. through a web form being confirmed to actually request joining a mailing list, instead of being added to the list without verification.
;Final, Ultimate Solution for the Spam Problem (FUSSP)
:An [[irony|ironic]] reference to naïve developers who believe they have invented the perfect spam filter, which will stop all spam from reaching users' inboxes while deleting no legitimate email accidentally.<ref>{{cite web|url=http://www.rhyolite.com/anti-spam/you-might-be.html|title=Vernon Schryver: You Might Be An Anti-Spam Kook If|publisher=Rhyolite.com|access-date=2012-12-10|archive-date=2012-10-14|archive-url=https://web.archive.org/web/20121014121719/http://www.rhyolite.com/anti-spam/you-might-be.html|url-status=live}}</ref><ref>{{cite web|title=Richi'Blog|url=http://richi.co.uk/blog/2006/04/tips-for-your-new-anti-spam-idea.html|website=richi.co.uk|language=en|access-date=2008-03-17|archive-date=2008-05-15|archive-url=https://web.archive.org/web/20080515192747/http://richi.co.uk/blog/2006/04/tips-for-your-new-anti-spam-idea.html|url-status=live}}</ref>

==History==
{{Main|History of email spam}}

==See also==
{{div col |colwidth=22em}}
* [[Address munging]]
* [[Anti-spam techniques]]
* [[Botnet]]
* [[Boulder Pledge]]
* [[CAUCE]]
* [[CAN-SPAM Act of 2003]]
* [[Chain email]]
* [[Direct Marketing Associations]]
* [[Disposable email address]]
* [[Email address harvesting]]
* [[Gordon v. Virtumundo, Inc.]]
* [[Happy99]]
* [[Junk fax]]
* [[List poisoning]]
* [[Make money fast]], the infamous Dave Rhodes chain letter that jumped to email.
* [[Netiquette]]
* [[news.admin.net-abuse.email]] newsgroup
* [[Advance fee fraud|Nigerian spam]]
* [[Project Honey Pot]]
* [[Pump and dump#Scam|Pump-and-dump stock fraud]]
* [[Shotgun email]]
* ''[[SPAMasterpiece Theater]]''
* [[Spamusement!]]
* [[Spambot]]
* [[SpamCop]]
* [[The Spamhaus Project|Spamhaus]]
* [[Spamtrap]]
* [[Spamware]]
* [[Spider trap]]
* [[VoIP spam|SPIT (SPam over Internet Telephony)]]
{{div col end}}

==References==
{{reflist}}

==Further reading==

* {{citation|last1=Dow|first1=K|last2=Serenko|first2=A|last3=Turel|first3=O|last4=Wong|first4=J|year=2006
|url=https://www.aserenko.com/papers/JeC_Dow.pdf|contribution=Antecedents and consequences of user satisfaction with email systems|title=International Journal of e-Collaboration|volume=2|number=2|pages=46–64}}.
* {{cite book|url=https://books.google.com/books?id=1gsUeCcA7qMC
|last1=Sjouwerman |first1=Stu |last2=Posluns |first2=Jeffrey|edition=1st |date=November 27, 2004
|title=Inside the spam cartel: trade secrets from the dark side |publisher=[[Elsevier]]/Syngress|isbn=978-1-932266-86-3}}

==External links==
'''Spam info'''
* {{citation|newspaper=The Economist|url=http://www.economist.com/displayStory.cfm?story_id=13851721|title=Can the Spam: How Spam is Bad for the Environment|date=June 15, 2009}}.

'''Spam reports'''
* {{citation|publisher=Barracuda Central|url=http://www.barracudacentral.com/index.cgi?p=spam|title=Worldwide Email Threat Activity|access-date=2008-03-18|archive-date=2008-03-28|archive-url=https://web.archive.org/web/20080328074328/http://www.barracudacentral.com/index.cgi?p=spam|url-status=dead}}.

'''Government reports and industry white papers'''
* {{citation|url=http://www.ftc.gov/opa/2005/11/spamharvest.pdf |title=Email Address Harvesting and the Effectiveness of Anti-SPAM Filters |location=United States |publisher=FTC |access-date=13 Oct 2007 |url-status=dead |archive-url=https://web.archive.org/web/20071128052940/http://www.ftc.gov/opa/2005/11/spamharvest.pdf |archive-date=2007-11-28 }}.
* [https://web.archive.org/web/20080706171420/http://www.eff.org/spam/ The Electronic Frontier Foundation's spam page] which contains legislation, analysis, and litigation histories
* {{usurped|1=[https://web.archive.org/web/20031004024511/http://www.spamhelp.org/articles/030319spamreport.pdf ''Why Am I Getting All This Spam? Unsolicited Commercial Email Research Six Month Report'']}} by Center for Democracy & Technology from the author of [[Pegasus Mail]] and [[Mercury Mail Transport System]] – [[David Harris (software developer)|David Harris]]
* {{citation|url=http://www.pegasusmail.tk/upload/SPAM_white_paper.pdf |title=Spam White Paper – Drowning in Sewage |publisher=Pegasus Mail |url-status=dead |archive-url=https://web.archive.org/web/20071128052944/http://www.pegasusmail.tk/upload/SPAM_white_paper.pdf |archive-date=2007-11-28 }}.

{{Spamming}}

{{DEFAULTSORT:E-Mail Spam}}
[[Category:Advertising]]
[[Category:Advertising by medium]]
[[Category:Email]]
[[Category:Digital marketing]]
[[Category:Marketing techniques]]
[[Category:Online advertising]]
[[Category:Promotion and marketing communications]]
[[Category:Spamming]]
[[Category:Internet fraud]]