On the World Wide Web, a link farm is any group of web pages that all hyperlink to every other page in the group. Although some link farms can be created by hand, most are created through automated programs and services. This NeXTcube used by Berners-Lee at CERN became the first Web server. ... A Web page or webpage is a resource on the World Wide Web, usually in HTML/XHTML format (the file extensions are typically htm or html) and with hypertext links to enable navigation from one page or section to another. ... A hyperlink, or simply a link, is a reference in a hypertext document to another document or other resource. ...

Link farms were developed by search engine optimizers in 1999 to take advantage of the Inktomi search engine's dependence upon link popularity. Although link popularity is used by some search engines to help establish a ranking order for search results, the Inktomi engine at the time maintained two indexes. Search results were produced from the primary index which was limited to approximately 100,000,000 listings. Pages with few inbound links continually fell out of the Inktomi index on a monthly basis. The success of the Google search engine was mainly due to its simple, easy-to-use, no-ad interface, and its powerful PageRank algorithm. ... Inktomi was a Californian company that provided software for Internet Service Providers, which was founded in 1996 by UC Berkeley professor Eric Brewer and graduate student Paul Gauthier. ...

Inktomi was targeted for manipulation through link farms because it was then used by several independent but popular search engines, such as HotBot. Yahoo!, then the most popular search service, also used Inktomi results to supplement its directory search feature. The link farms helped stabilize listings for (normally) online business Web sites that had few natural links from larger more stable sites in the Inktomi index. Inktomi was a Californian company that provided software for Internet Service Providers, which was founded in 1996 by UC Berkeley professor Eric Brewer and graduate student Paul Gauthier. ... Hotbot Hotbot was one of the early Internet search engines and was launched in May 1996 as a service of Wired Magazine. ... ... Inktomi was a Californian company that provided software for Internet Service Providers, which was founded in 1996 by UC Berkeley professor Eric Brewer and graduate student Paul Gauthier. ...

Link farm exchanges were at first handled on an informal basis, but several service companies were founded to provide automated registration, categorization, and link page updates to member Web sites.

When the Google search engine became popular, search engine optimizers learned that Google's ranking algorithm depended in part on a link weighting scheme called PageRank. Rather than simply count all inbound links equally, the PageRank algorithm determines that some links may be more valuable than others, and therefore assigns them more weight than others. Link farming was adapted to help increase the PageRank of member pages. Google Inc. ... PageRank, sometimes abbreviated to PR, is a family of algorithms for assigning numerical weightings to hyperlinked documents (or web pages) indexed by a search engine originally developed by Larry Page (thus the play on the words PageRank). ... PageRank, sometimes abbreviated to PR, is a family of algorithms for assigning numerical weightings to hyperlinked documents (or web pages) indexed by a search engine originally developed by Larry Page (thus the play on the words PageRank). ...

However, even the link farms became susceptible to manipulation by unscrupulous Webmasters who joined the services, received inbound linkage, and then found ways to hide their outbound links or to avoid posting any links on their sites at all. Link farm managers had to implement quality controls and monitor member compliance with their rules to ensure fairness.

Alternative link farm products emerged, particularly link-finding software that identified potential reciprocal link partners, sent them template-based emails offering to exchange links, and create directory-like link pages for Web sites hoping to build their link popularity and PageRank.

Search engines countered the link farm movement by identifying specific attributes associated with link farm pages and filtering those pages from indexing and search results. In some cases, entire domains were removed from the search engine indexes in order to prevent them from influencing search results.

The justification for link farm-influenced crawling diminished proportionately as the search engines expanded their capacities to index more sites. Once the 500,000,000 listing threshold was crossed, link farms became unnecessary for helping sites stay in primary indexes. Inktomi's technology, now a part of Yahoo!, now indexes billions of Web pages and uses them to offer its search results.

Where link weighting is still believed by some Webmasters to influence search engine results with Google, Yahoo!, MSN, and Ask (among others), link farms remain a popular tool for increasing PageRank or perceived equivalent values. PageRank-like measurements apply only to the individual pages being linked to (typically the reciprocal linking pages on member sites), so these pages must in turn link out to other pages (such as the main index pages of the member sites) in order for the link weighting to help. MSN (or The Microsoft Network) a collection of internet services provided by Microsoft. ... Ask can be used to refer: Amplitude-shift keying a telecommuncations term Ask and Embla about Norse Mythology Ask Jeeves This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...

Google indicates in its Webmaster Guidelines that more than 100 factors are used to determine search results rankings. There is considerable debate in the search engine optimization community regarding the continued value of PageRank. Mike Grehan, a well-known search engine optimization columnist, has publicly quoted engineers from Yahoo! and Ask who say Google never fully implemented their PageRank algorithm.

The expression "link farm" is now considered to be pejorative and derogatory. Many reciprocal link management service operators tout the value of their resource management and direct networking relationship building. The reciprocal link management services promote their industry as an alternative to search engines for finding and attracting visitors to Web sites. Their acceptance is by no means universal but the link management services seem to have established a stable customer base. Look up pejorative on Wiktionary, the free dictionary. ... A word or phrase is pejorative or derogatory (sometimes misspelled perjorative) if it expresses contempt or disapproval; dyslogistic (noun: dyslogism) is used synonymously (antonyms: meliorative, eulogistic, noun eulogism). ...

Search engines such as Google recommend that webmasters request relevant links to their sites (conduct a link campaign), but avoid participating in link farms. According to Google, a site that participates in a link farm may have its search rankings penalized. The success of the Google search engine was mainly due to its simple, easy-to-use, no-ad interface, and its powerful PageRank algorithm. ... Google Inc. ... A webmaster (or webmistress for females) is a person responsible for designing, developing, marketing, or maintaining website(s). ... Link campaigns are a form of online marketing and is also a method for search engine optimization. ...

See also

• Server farm
• Reciprocal link
• Spamdexing
• Link spam
• Doorway pages
• Cloaking
• Keyword stuffing
• Web guide
• Link campaign
• Scraper site

A typical server farm. ... A reciprocal link is a mutual link between two objects, commonly between two websites in order to ensure mutual traffic. ... Spamdexing or search engine spamming is the practice of deliberately and dishonestly manipulating search engines to increase the chance of a website or page being placed close to the beginning of search engine results, or to influence the category to which the page is assigned in a dishonest manner. ... Link spam (also called blog spam or comment spam) is a form of spamming or spamdexing that recently became publicized most often when targeting weblogs (or blogs), but also affects wikis (where it is often called wikispam), guestbooks, and online discussion boards. ... Doorway pages are web pages that are created to rank high in search engines for particular phrases with purpose to seduce or hoax you to watch another page. ... Cloaking is a search engine optimization technique in which the content presented to the search engine spider is different from that presented to the users browser; this is done by delivering content based on the IP addresses or the User-Agent HTTP header of whatever is requesting the page. ... Keyword stuffing is considered to be a unethical Search engine optimization (SEO) technique. ... A web portal is a web site that provides a starting point or gateway to other resources on the Internet or an intranet. ... Link campaigns are a form of online marketing and is also a method for search engine optimization. ... A scraper site is a website that pulls all of its own information from other websites. ...

External links

• Google Information for Webmasters, accessed 2005-09-03.