The whole concept of the no-follow tag is definitely interesting, it’s effectiveness is questionable and as far as comment spam goes, it hasn’t helped. (Thank God for Akismet) As far as it’s use in day to day operations of the web, it is somewhat un-spoken about, I have always thought that links that use the no-follow tag should be indicated as such, so the user can tell if the publisher of the website actually “believes” in that link. It is one thing to link somewhere, but another thing to say I actually respect the linked website enough that I will give it my vote. It’s somewhat like democracy really, it’s one thing to complain about the current administration or government, but you don’t really have that right unless you actually vote.
Anyway, there is a pretty broad assumption that search engines respect no-follow completely – never using that link in the Pagerank algorithm. Duncan Riley from TechCrunch suggests that it has pretty much solved the problem of people gaming Wikipedia which is feasible, but who is to say that Google actually ignores those links. Wikipedia’s content is generally very good and I think it is just far too good for any ranking algorythm to ignore.
We know there are 2.345 million variables (this number may be wrong) that Google uses to rank websites, so why wouldn’t it use links from Wikipedia as another indicator of relevance. The obvious problem that this approach encounters is verifying the integrity of the links. This could be done relatively accurately by time, if the link has been there for a month then include it in the index.
I would love to hear your thoughts on this.