Nofollow Tag - definition
The “nofollow tag” is an html attribute that was invented by Google in order to prevent or reduce comment spam, especially weblog related. It is used by webmasters on their webpages and tells the search engine spiders not to count links tagged with it for link popularity calculation systems such as the Google Pagerank system ™. When used, the “nofollow” tagged link will not count as a vote for the link target url and will therefore not increase its SERPS (Search Engine Result Pages) ranking in any way.
The “nofollow” tag and its influence on Comment Spam
“Comment Spam” is a condemned “off page Search Engine Optimization” technique used by “black hat SEOs” to increase a website’s link popularity and, as a result, its SERPS ranking.
How does comment spamming work?
Comment Spammers search for interactive webpages such as forums, webblogs or wikipedias that are very well ranked in the search engines and where it’s possible to leave a reply to an article. Then they post links to their own webpages there, mostly unrelated to the original topic and with commercial purposes in mind.
The theoretical effect of the “nofollow tag” on comment spam
The nofollow tag was invented as a prevention measure to fight comment spam - it reduces the benefits of link spamming.
SEO - benefits of link spamming without “nofollow tag”:
- Pagerank and Link popularity
- Additional visitors
- Website spidered more often
SEO - benefits of link spamming with “nofollow tag”:
- Additional visitors
- Website spidered more often (spiders still follow the link)
The practical effect of the “nofollow tag” on comment spam
Since its introduction in January 2005, the total amount of comment spam was reduced, but not as significantly as expected. Possible reasons are on one hand the slightly low level of awareness of both parties, webmasters and spammers and on the other hand the fact that there are still benefits of link spamming left, as described before.
Negative side effects of the nofollow tag on the blogging community
Right after blogging started, the blogging community grew very tall in a short amount of time, thanks to several factors, such as the high affinity of bloggers to create link networks between each other which give them preferred SERPS rankings.
Looking into the future, especially this factor might be in peril since more and more bloggers are using the “nofollow tag”. As a result, the overall link popularity of blogs might tend to drop, lowering their overall importance and influence on the internet as whole.
Recapitulating evaluation of the nofollow tag
The “nofollow tag” is definately not the holy grail in spam prevention, however it might be useful, if employed moderately where necessary. It is crucial to spread information about the “nofollow tag” among webmasters as well as among spammers to maximize the positive influence on spam prevention, until, hopefully soon - there is another, more effective measure to fight comment spam.