The concept of the terminology rel = “no follow” has evolved from Google’s Webspam Head Matt Cutts and Jason Shellen in 2005. The term rel = “no follow” is HTML attribute, it is used for instructing search engines to avoid using hyper links for influencing link ranking in search engines’ index. The objective behind its usage is to reduce the spread of certain search engine spam thereby improving the quality of search engine results. The attribute “no follow” was originally designed to stop comments on blogs. This attribute value does not imply that it blocks access to content and prevents them from being indexed by search engines. However, the manner in which the attribute is interpreted differs between search engines as some of them literally do not follow the links to the pages the site has been linked to while other search engines still “follow” the links to locate new pages for indexing.
To some the term rel = “no follow” infers to search engines “don’t score the link” rather than “don’t follow the link”. Initially this “no follow” attribute was noticed in the Meta tag of pages which instructed the search engines not to crawl the outgoing links of that particular web page.
But preventing robots from crawling individual page links require great deal of effort and this accounted for the “no follow” attribute value of the rel being developed. This gave webmasters more granularity and control as it could inform robots not to crawl a specific link.
Search engine Google introduced the rel = “no follow” tag to help sites differentiate between links they put in the sites they trust and links they put up in certain sites without fully trusting that site. These links are not counted as back links by Google and it implies that the site would not get a higher page rank from the link which has rel = “no follow” on it. When the “no follow” attribute is added, this attribute segment is usually shown in “bold”. Similarly, forums put up rel = “no follow” tags on signatures which disallow people from posting only on that link. In certain cases, the forums leave out the tag believing that people contributing to the forum deserve the benefit of those links.
Even in blogs, spam is a pervasive problem. The same dynamics are prevalent as in forum where the rel = “no follow” tag dissuades people from posting. Many believe that links help the site in attracting visitors and attain page rank. The search engine Google feels that links which are purchased should apply rel =”no follow” tag. Google adheres to this rule as it believes no links should be sold for page rank purposes. In some cases, Firefox extensions highlights rel = “no follow” links to assist webmasters and SEO experts to determine whether the links are for page ranking purposes.
The term rel = “no follow” is considered an elemental micro format that implies a hyperlink destination which has this tag should not be ranked by user agents who perform link analysis on web pages. This action indicates that links developed by third party web users like commentators on blogs or links that though being hyperlinks of websites avoids endorsing the same.