7th Jan 2009
Well, first off - some people just blatantly misunderstand the rel=nofollow attribute's purpose. Not only do they misuse it, but they don't even know what it really is, in the technical sense. Many people call it the rel=nofollow tag. This is inaccurate. It's an anchor-tag attribute, and not a tag in and of itself.
Secondly. The attribute was devised as a way for Webmasters to identify or "flag" links of unknown or potentially poor quality, such as those in user-generated content, e.g. blog comments, forum posts, etc. Thusly flagged links would therefore not be "followed" by search engine crawlers, hence the "nofollow". Since they are not followed, PageRank (PR) does not flow out to the linked page.
In my opinion, this unnatural restriction of PR propagation by using the rel=nofollow attribute is a bad thing, mostly because some Webmasters have misinterpreted the concept and taken it to an extreme. The misinterpretation, I believe, has to do with "engineering" of the flow of PageRank (PR). It is commonly believed that using the rel=nofollow attribute on links to pages that don't need to rank in search engines e.g. contact pages, terms and conditions pages, etc., will basically save the PR and redirect it to other "more important" pages, such as product pages, where a search engine ranking would be much more desirable. This engineering of PR flow is thought to produce better results for the pages that are to rank.
This is a fallacy, in my belief. It is counterintuitive to believe that a search engine would allow a Webmaster to manipulate the PR of his/her own Websites. Furthermore, it should be noted that the Google PageRank (PR) formula is a form of probability calculation. Its fundamental purpose is to analyze the link structure of the Web and determine the probability that a given user will land on a specific page (page X). Among the considered factors are the total number of pages on the Internet, the total number of links, and the number of links to page X. When the PR for a page is determined, then that PR that can be "passed on" to other pages through links. It is divided up among each of the links on the page (not equally, but that's for another article!). This reflects the probability that a user can only click on one link (at least, one at a time).
The important thing to note is that the rel=nofollow attribute does not make links invisible (search engines may ignore them, but they're still there). Therefore, given a page with 10 links, the probability score of which link the user will click on remains the same, regardless of whether or not any of the links use a rel=nofollow attribute. We must therefore assume that PR assigned to links using the rel=nofollow attribute simply goes into a "black hole", since it doesn't get passed on to the linked page, and it doesn't make sense that it be reallocated to other links on the page (since rel=nofollow doesn't affect probability).
Given this important factor, it would seem superfluous to use the rel=nofollow attribute on less desirable pages in an attempt to engineer the flow of PR to more desirous ones.
A second strike against the overuse of rel=nofollow is much easier to understand: Perception of Quality. If it's true that rel=nofollow is basically a way of saying that a link shouldn't be trusted (stemming from the fact that it's not worth the PR), and if there are many such links on a site, then what does that say about the overall trustability of the Website. For me, it says that it's potentially full of low quality junk and "spammy" links!
One last thing I'd like to mention is that of perversion (in the non-sexual sense!). It is my belief that the rel=nofollow attribute should be made redundant, for the very simple fact that it has been overused to the point where it may be perverting the development of the Web and organic search engine rankings. Since many blogs and forums now use this attribute on outbound links, many of the topically relevant inline links provided by participants on such sites are discounted in the eyes of search engines, even though they may even be of extremely high value. Search engines should evaluate such valuable links. And, I believe that they may do so, even for links with rel=nofollow!
The final prescription: use rel=nofollow attributes only where you have to!
This is a fascinating perspective on this clumsy thing. Thanks.
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