Wikipedia announced recently that it is going back to adding the “nofollow” attribute to its outbound links in an attempt to keep people from gaming the system to leach linkjuice off the the site for personal gain.

According to Google, “when Google sees the attribute (rel=”nofollow”) on hyperlinks, those links won’t get any credit when we rank websites in our search results.” So the theory is that by denying linkjuice Wikipedia will stem article spam.

NoFollow has always been controversial, and the response to Wikipedia’s decision has been mixed. Rand Fishkin at SeoMoz (which has also instituted NoFollow) says Wikipedia has finally made the right decision. But he offers surprisingly little to defend that position.

Peter Da Vanzo at blog.v7n.com says the decision has scant significance:

Here’s a question: why do people assume that if Wikipedia adds nofollow, then the links won’t count in search engine calculations? It wouldn’t take much for the search engines to make Wikipedia a special case, and ignore the nofollow tag, if that isn’t the case already.

And another: How do people know that Wikipedia was passing any (real) PageRank or authority before? There are many pages which aren’t using the nofollow tag that also aren’t passing any measurable PageRank and/or authority, probably due to some hand tweaking.

Barry Welford thinks search engines are running up against Heisenberg’s Uncertainty Principle:

In a sense, Wikipedia is correcting the fallacy in the whole Google PageRank approach. It’s like Heisenberg’s Uncertainty Principle. There are some things you can’t measure. If you try to measure them then they’re not the same. Once Google says inlinks will boost a web page’s relevancy, then of course everyone, often supercharged with dumb computer programs, generates as many inlinks as they can.

My opinion? I don’t like NoFollow. I think it amounts to trying to get a free ride by benefiting from links without paying the cost for them. In fact, I’ve added a plug-in that removes the default NoFollow from my blog comments. If anyone wants to comment, I can approve or deny the comment, so the onus is on me to decide whether the link should stand. If commenters have added something of value then I think they deserve any link benefit I can give back to them (my home page, btw, is currently PR6).

I also feel that NoFollow will have little if any effect on the value of Wikipedia contributions. Even with NoFollow, links still bring traffic, and since Wikipedia is likely to continue to rank high in the SERPs, scam sites will still benefit from Wikipedia links if they can get them. In fact, a lot of the spam links submitted to this blog already have the NoFollow tag embedded. By instituting NoFollow, Wikipedia probably hurts honest sites more than scammers — just the sites that took Wikipedia to the top of the SERPs by linking to them in the first place.

So put me in the camp of the sensible Philipp Lenssen who writes at Google Blogoscoped:

What happens as a consequence, in my opinion, is that Wikipedia gets valuable backlinks from all over the web, in huge quantity, and of huge importance — normal links, not “nofollow” links; this is what makes Wikipedia rank so well — but as of now, they’re not giving any of this back. The problem of Wikipedia link spam is real, but the solution to this spam problem may introduce an even bigger problem: Wikipedia has become a website that takes from the communities but doesn’t give back, skewing web etiquette as well as tools that work on this etiquette (like search engines, which analyze the web’s link structure). That’s why I find Wikipedia’s move very disappointing.

Perhaps the most interesting response to the news came from Andy Beal at Marketing Pilgrim. He is adding NoFollow to links to Wikipedia from his site.

UPDATE, 24 JAN. Andy Beard has made a Wikipedia NoFollow plug-in, and Aaron Pratt offers a good commentary.