A no follow code, or no follow, is a code that is a non-standard HTML attribute value used to signify to search engines that when a particular hyperlink is clicked on, it should not affect the ranking of the website in the search engine. This code was developed in 2005 by the head of Google.com’s webspam team to reduce the effectiveness of certain types of search engine spam. No follow codes improve the quality and number of relevant links when a search query is initiated by a visitor, and prevents spamdexing or other black hat search engine optimization tactics.
A no follow code does not block the content of a web page from view or prevent the indexing of content. The intention of the no follow code is the prevention of spam and spamdexing. Its design was such that other codes like Robots.txt would be more appropriate when web pages are coding what should and should not be crawled by search engine spiders. Also of importance is that while the no follow code prevents spamdexing, it prevents pay per click ads from contributing to the rankings of the advertised websites.
The major search engines on the Internet, such as Google, Yahoo!, MSN, and Ask all recognize theno follow code within the HTML of web pages listed in the indexes of these search engines. While smaller search engines may not recognize the code, more are adapting as the no follow code increases in popularity. The majority of Internet software also recognizes and uses the no follow code.