*The following guest post is by Duncan*
After reading a couple of posts on this site and seeing just how worked up people are getting over the whole ‘no-follow’ link business. I thought I would chuck my thoughts into the mixer and try to clear up a few things.
Firstly, the no-follow attribute (it’s not a tag) on links was first introduced back in 2005 by the Big G. They said that if you add rel=”nofollow” to your links then those links “won’t get any credit when we rank websites”. MSN and Yahoo! Quickly jumped onboard and said they would support the new initiative as well.
Even back then there was a level of mis-trust surrounding Google, and so webmasters and SEOs took it upon themselves to test this new ‘no-follow’ theory. Some found that the no-follow attribute did indeed work and sites did not get any power when linked to with no-follow links. Others have since claimed that power is still passed through no-follow links.
There was even speculation over whether Google actually crawled and indexed pages that had only been linked to using no-follow links. Unfortunately, there has never (to the best of knowledge) been extensive research conducted on this topic and certainly no categorical evidence on the matter published on highly-trustworthy sites. Instead, we have been left with much hearsay and speculation about whether no-follow actually works or not.
However, what we have got are indications and hints from the search engines that we can use to piece together some idea of the truth.
Firstly, we can use logic to determine what is in the best interests of the search engines. Spam is a massive problem for them and we know that websites sometimes need to link out to other sites that they don’t necessarily want to pass power to. For example, they might want to warn about a spammy or scammy website, but at the same time not help it rank. Also, many large websites cannot look after every link on the site and so are open to link spam. With this in mind it makes perfect sense for search engines to introduce a method for maintaining clean hyperlinks, but not ‘voting’ for the site being linked to. I’ll also add to this argument that in my experience I have never seen no-follow links pass any power that has gone on to help rankings.
There is another argument as well that comes about from Google shooting itself in the foot somewhat. By introducing the no-follow attribute, webmasters and SEOs soon realised that they could use these links to craft the internal power of their sites to make some of their pages more powerful than others (PageRank sculpting). Additionally, some sites starting adopting Black Hole SEO techniques, not linking out to any websites without using no-follow links, thus maintaining all link juice power in the site. The link juice does not leak out, but instead gets recycled internally and arguable increases exponentially, leading to very power websites.
Google obviously did not like the abusing of their very clever link attribute and so Matt Cutts wrote a post about how Google had changed the algorithm so no-follow internal links now wasted link juice. He claimed although no power was passed through them, no-follow links were still including in how many times the power of a page was divided between the links. Incidentally I don’t believe a word of this, but that doesn’t matter, what is more important is what it implied. This move cemented for me that fact that no-follow links do not pass power, otherwise Google would not have bothered telling website owners not to use it.
Crawl & Index?
In terms of whether search engines crawl and index pages that have nothing but no-follow links pointing to them, there are unfortunately not as many clues. However, it is my personally opinion that it does follow those links as Google very nosey and tends to want to know what is going on in every corner of the web. These pages rarely rank though as they have no power to move them up the SERPS. Again, from experience I have seen pages cached that having nothing but no-follow links. Even Google is not definitive on the matter saying “In general, we don’t follow them”, which obviously means that they can and do.
In semi-conclusion then: no-follow links do not pass power, but are crawled and sometimes indexed by Google. I cannot really speak for other the other search engines, but then I’m not sure I care about them.