Why wouldn’t I want the search engine spiders to see all of the links on my site? (Or, Why would I use “nofollow”?)
There are many reasons you would want to use the “nofollow” tag, such as:
- Paid Links: This is recommended by Google. Essentially, your sites page rank give a small amount of rank juice to the sites you link to (which helps their search engine ranking, which is the purpose of link building, to get that juice from others). If you have a paid link on your site, it’s essentially buying a higher rank in Google. They don’t like that.
- Maybe in your blog’s comment section (if using most blog software, this is automatic). It is up to you if you want your commentators to get link juice back to their site. It is personal preference.
- When linking to major, very popular sites. If you are linking to google.com, yahoo.com, digg.com (the front page), cnn.com, or whoever else, they are already popular, so you might as well use “nofollow” since your link won’t make or break them.
Another information about Nofollow:
nofollow is an HTML attribute value used to instruct some search engines that a hyperlink should not influence the link target’s ranking in the search engine’s index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing from occurring.
The concept for the specification of the attribute value nofollow was designed by Google’s head of webspam team Matt Cutts and Jason Shellen from Blogger.com in 2005. The specification for nofollow is copyrighted 2005-2007 by the authors and subject to a royalty free patent policy, e.g. per the W3C Patent Policy 20040205, and IETF RFC 3667 & RFC 3668. The authors intend to submit this specification to a standards body with a liberal copyright/licensing policy such as the GMPG, IETF, and/or W3C.
The nofollow attribute value is not meant for blocking access to content, or for preventing content to be indexed by search engines. The proper methods for blocking search engine spiders to access content on a website or for preventing them to include the content of a page in their index are the Robots Exclusion Standard (robots.txt) for blocking access and on-page Meta Elements that are designed to specify on an individual page level what a search engine spider should or should not do with the content of the crawled page.
MediaWiki software, which powers Wikipedia, was equipped with nofollow support soon after initial announcement in 2005. The option was enabled on most Wikipedias. One of the prominent exceptions was the English Wikipedia. Initially, after a discussion, it was decided not to use rel=”nofollow” in articles and to use a URL blacklist instead. In this way, English Wikipedia contributed to the scores of the pages it linked to, and expected editors to link to relevant pages.
In May 2006, a patch to MediaWiki software allowed to enable nofollow selectively in namespaces. This functionality was used on pages that are not considered to be part of the actual encyclopedia, such as discussion pages and resources for editors. Following increasing spam problems and a within-Foundation order from Jimmy Wales, rel=”nofollow” was added to article-space links in January 2007. However, the various interwiki templates and shortcuts that link to other Wikimedia Foundation projects and many external wikis such as Wikia are not affected by this policy.
Other websites like Slashdot, with high user participation, use improvised nofollow implementations like adding rel=”nofollow” only for potentially misbehaving users. Potential spammers posing as users can be determined through various heuristics like age of registered account and other factors. Slashdot also uses the poster’s karma as a determinant in attaching a nofollow tag to user submitted links.
Social bookmarking and photo sharing websites that use the rel=”nofollow” tag for their outgoing links include YouTube; websites that don’t use the rel=”nofollow” tag include Digg.com, Furl, Propeller.com (formerly Netscape.com), Yahoo! My Web 2.0, and Technorati Favs.
Search engines have attempted to repurpose the nofollow attribute for something different. Google began suggesting the use of nofollow also as a machine-readable disclosure for paid links, so that these links do not get credit in search engines’ results.
The growth of the link buying economy, where companies’ entire business models are based on paid links that affect search engine rankings, caused the debate about the use of nofollow in combination with paid links to move into the center of attention of the search engines, who started to take active steps against link buyers and sellers. This triggered a very strong response from web masters.
Sourced from inlineseo.com & wikipedia.org.