Editing Anti-spam techniques (section)

==End-user techniques==

There are a number of techniques that individuals can use to restrict the availability of their email addresses, with the goal of reducing their chance of receiving spam.

===Discretion===
Sharing an email address only among a  limited group of correspondents is one way to limit the chance that the address will be "harvested" and targeted by spam. Similarly, when forwarding messages to a number of recipients who don't know one another, recipient addresses can be put in the  "[[Blind carbon copy|bcc: field]]" so that each recipient does not get a list of the other recipients' email addresses.

===Address munging===
{{Main|Address munging}}

Email addresses posted on [[webpage]]s, [[Usenet]] or [[chat rooms]] are vulnerable to [[e-mail address harvesting]].<ref>[http://www.ftc.gov/bcp/conline/pubs/alerts/spamalrt.htm Email Address Harvesting: How Spammers Reap What You Sow] {{webarchive |url=https://web.archive.org/web/20060424083903/http://www.ftc.gov/bcp/conline/pubs/alerts/spamalrt.htm |date=April 24, 2006 }}, Federal Trade Commission. URL accessed on 24 April 2006.</ref> Address munging is the practice of disguising an [[e-mail address]] to prevent it from being automatically collected in this way, but still allow a human reader to reconstruct the original: an email address such as, "<nowiki>no-one@example.com</nowiki>", might be written as "no-one at example dot com", for instance. A related technique is to display all or part of the email address as an image, or as jumbled text with the order of characters restored using [[CSS]].

===Avoid responding to spam===
A common piece of advice is to not to reply to spam messages<ref>[http://itsecurity.vermont.gov/threats "Information Technology: Threats"] {{webarchive|url=https://web.archive.org/web/20160307005112/http://itsecurity.vermont.gov/threats |date=2016-03-07 }}, vermont.gov</ref> as spammers may simply regard responses as confirmation that an email address is valid. Similarly, many spam messages contain web links or addresses which the user is directed to follow to be removed from the spammer's mailing list – and these should be treated as dangerous. In any case, sender addresses are often forged in spam messages, so that responding to spam may result in failed deliveries – or may reach completely innocent third parties.

===Contact forms===

Businesses and individuals sometimes avoid publicising an email address by asking for contact to come via a "contact form" on a webpage – which then typically forwards the information via email. Such forms, however, are sometimes inconvenient to users, as they are not able to use their preferred email client, risk entering a faulty reply address, and are typically not notified about delivery problems. Further, contact forms have the drawback that they require a website with the appropriate technology.

In some cases contact forms also send the message to the email address given by the user. This allows the contact form to be used for sending spam, which may incur email deliverability problems from the site once the spam is reported and the sending IP is blacklisted.

===Disable HTML in email===
{{Main|HTML email}}

Many modern mail programs incorporate [[web browser]] functionality, such as the display of [[HTML]], URLs, and images.

Avoiding or disabling this feature does not help avoid spam. It may, however, be useful to avoid some problems if a user opens a spam message: offensive images, obfuscated hyperlinks, being tracked by [[web bug]]s,  being targeted by [[JavaScript]] or attacks upon security vulnerabilities in the HTML renderer. Mail clients which do not automatically download and display HTML, images or attachments have fewer risks, as do clients who have been configured to not display these by default.

===Disposable email addresses===
{{Main|Disposable email address}}

An email user may sometimes need to give an address to a site without complete assurance that the site owner will not use it for sending spam. One way to mitigate the risk is to provide a ''disposable'' email address — an address which the user can disable or abandon which forwards email to a real account. A number of services provide disposable address forwarding. Addresses can be manually disabled, can expire after a given time interval, or can expire after a certain number of messages have been forwarded.
Disposable email addresses can be used by users to track whether a site owner has disclosed an address, or had a [[Data Security|security breach]].<ref>[http://www.securityfocus.com/news/11488 Customers: TD Ameritrade failed to warn of breach] {{webarchive|url=https://web.archive.org/web/20120305064417/http://www.securityfocus.com/news/11488 |date=2012-03-05 }}</ref>

===Ham passwords===
Systems that use "ham passwords" ask unrecognised senders to include in their email a password that demonstrates that the email message is a "ham" (not spam) message. Typically the email address and ham password would be described on a web page, and the ham password would be included in the subject line of an email message (or appended to the "username" part of the email address using the "[[Email address#Address tags|plus addressing]]" technique). Ham passwords are often combined with filtering systems which let through only those messages that have identified themselves as "ham".<ref name="ham">David A. Wheeler, (May 11, 2011) [http://www.dwheeler.com/essays/spam-email-password.html Countering Spam by Using Ham Passwords (Email Passwords)] {{webarchive|url=https://web.archive.org/web/20120204050500/http://www.dwheeler.com/essays/spam-email-password.html |date=2012-02-04 }}</ref>

===Reporting spam===
{{Main|Spam reporting}}
Tracking down a spammer's ISP and reporting the offense can lead to the spammer's service being terminated<ref>This depends on provider's policy; for example: {{cite web |url=https://www.godaddy.com/agreements/showdoc.aspx?pageid=UTOS |title=Universal Terms of Service Agreement |author=Go Daddy Legal Department |website=GoDaddy.com |access-date=5 September 2014 |quote=We do not tolerate the transmission of spam. We monitor all traffic to and from our web servers for indications of spamming and maintain a spam abuse complaint center to register allegations of spam abuse. Customers suspected to be using our products and services for the purpose of sending spam are fully investigated. If we determine there is a problem with spam, we will take the appropriate action to resolve the situation. |url-status=live |archive-url=https://web.archive.org/web/20140704022053/http://www.godaddy.com/agreements/ShowDoc.aspx?pageid=UTOS |archive-date=4 July 2014 }}</ref> and criminal prosecution.<ref>The latter depends on local law; for example: {{cite web |url=http://fightspam.gc.ca/eic/site/030.nsf/eng/home |title=Canada's Law on Spam and Other Electronic Threats |author=<!--Staff writer(s); no by-line.--> |website=fightspam.gc.ca |access-date=5 September 2014 |quote=Canada's anti-spam legislation (CASL) is in place to protect Canadians |url-status=live |archive-url=https://web.archive.org/web/20140910102318/http://fightspam.gc.ca/eic/site/030.nsf/eng/home |archive-date=10 September 2014 }}</ref>  Unfortunately, it can be difficult to track down the spammer, and while there are some online tools such as [[SpamCop]] and Network Abuse Clearinghouse to assist, they are not always accurate. Historically, reporting spam in this way has not played a large part in abating spam, since the spammers simply move their operation to another URL, ISP or network of IP addresses.

In many countries consumers may also report unwanted and deceptive commercial email to the authorities, e.g. in the US to the [[Federal Trade Commission|US Federal Trade Commission]] (FTC),<ref>[http://www.onguardonline.gov/articles/0038-spam/ "Spam"] {{webarchive|url=https://web.archive.org/web/20131217053600/http://www.onguardonline.gov/articles/0038-spam/ |date=2013-12-17 }}, OnGuardOnline.gov</ref> or similar agencies in other countries.<ref>[https://www.dia.govt.nz/Services-Anti-Spam-Index "Anti-spam"] {{webarchive|url=https://web.archive.org/web/20160224003034/http://www.dia.govt.nz/Services-Anti-Spam-Index |date=2016-02-24 }}, NZ Department of Internal Affairs</ref>