What is nofollow?
nofollow is a value that can be assigned to the rel attribute of an HTML a element 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 internet advertising because their search algorithm depends heavily on the amount of links to a website when determining which websites should be listed in what order in their search results for any given term.
How does it work?
The major search engine providers (Google, Yahoo!, and MSN) got together and came up with a way to fight this form of link spam – the rel=”nofollow” attribute. And now, most blog software programs add this attribute to links in comments automatically.
When a search engine spider comes to a page with links on it, the standard response is to index the page and then follow all the links on the page. That is when the search engine looks at the links to see which ones you have “voted” for by putting them on your page. When the search engine spider sees nofollow on the link, it does the following:
- Does not follow the link to the new site
- Does not count the link towards it’s popularity score in their ranking engine
- Does not include the link text in the relevancy score for those keywords
Search engines will not penalize your site or blog for links that have nofollow on them. It also doesn’t prevent a site from ever being indexed in Google. And putting nofollow on links does not imply any judgement about those links. In other words, if you apply the nofollow attribute to a link you aren’t saying that you think it’s bad or spam, just that the link isn’t yours and shouldn’t be followed by search engines.
How does your search engine treat the No Follow attribute?
Google : The Googlebot does not follow that link.
Yahoo : If we find a link we make it available to our algorithms to find new content, whether it has a ‘no follow’ attribute or not. However, if the ‘no follow’ attribute is present, it means that no attribution is given to the target from the source of the link.
Ask.com : We have never officially supported No Follow, so your questions don’t apply to our crawler/ranking.