Editing Spamdexing (section)

=== Using world-writable pages ===
{{main|Forum spam}}
Web sites that can be edited by users can be used by spamdexers to insert links to spam sites if the appropriate anti-spam measures are not taken.

Automated [[spambot]]s can rapidly make the user-editable portion of a site unusable.
Programmers have developed a variety of automated [[Forum spam#Spam prevention|spam prevention techniques]] to block or at least slow down spambots.

====Spam in blogs====
{{main|Spam in blogs}}
Spam in blogs is the placing or solicitation of links randomly on other sites, placing a desired keyword into the hyperlinked text of the inbound link. Guest books, forums, blogs, and any site that accepts visitors' comments are particular targets and are often victims of drive-by spamming where automated software creates nonsense posts with links that are usually irrelevant and unwanted.

====Comment spam====
Comment spam is a form of link spam that has arisen in web pages that allow dynamic user editing such as [[wikis]], [[blogs]], and [[guestbooks]]. It can be problematic because [[Software agent|agents]] can be written that automatically randomly select a user edited web page, such as a Wikipedia article, and add spamming links.<ref name=Mishne>{{cite conference | first = Gilad | last = Mishne | author-link = Gilad Mishne | author2 = David Carmel | author3 = Ronny Lempel | title = Blocking Blog Spam with Language Model Disagreement | book-title = Proceedings of the First International Workshop on Adversarial Information Retrieval on the Web | year = 2005 | url = http://airweb.cse.lehigh.edu/2005/mishne.pdf | access-date = 2007-10-24 | conference = | archive-date = 2011-07-21 | archive-url = https://web.archive.org/web/20110721071748/http://airweb.cse.lehigh.edu/2005/mishne.pdf | url-status = live }}</ref>

====Wiki spam====
Wiki spam is when a spammer uses the open editability of [[wiki]] systems to place links from the wiki site to the spam site.

====Referrer log spamming====
[[Referrer spam]] takes place when a spam perpetrator or facilitator accesses a [[web page]] (the ''referee''), by following a link from another web page (the ''[[referrer]]''), so that the referee is given the address of the referrer by the person's web browser. Some [[website]]s have a referrer log which shows which pages link to that site. By having a [[Internet bot|robot]] randomly access many sites enough times, with a message or specific address given as the referrer, that message or Internet address then appears in the referrer log of those sites that have referrer logs. Since some [[Web search engine]]s base the importance of sites on the number of different sites linking to them, referrer-log spam may increase the search engine rankings of the spammer's sites.  Also, site administrators who notice the referrer log entries in their logs may follow the link back to the spammer's referrer page.

==== Countermeasures ====
Because of the large amount of spam posted to user-editable webpages, Google proposed a "nofollow" tag that could be embedded with links. A link-based search engine, such as Google's [[PageRank]] system, will not use the link to increase the score of the linked website if the link carries a nofollow tag. This ensures that spamming links to user-editable websites will not raise the sites ranking with search engines. Nofollow is used by several websites, such as [[WordPress|Wordpress]], [[Blogger (service)|Blogger]] and [[Wikipedia]].{{citation needed|date=October 2012}}