Over the weekend, Wikipedian-in-Chief Jimmy Wales  decreed  that all links on the site would be tagged as "No Follow." That means, in essence, that the links become invisible to search engines like Google's. The engines won't take the links into account in ranking search results. Wikipedia is adopting the policy to reduce spammers' incentives to add spam links to the encyclopedia. I wonder, though, if it could also have the effect of reinforcing Wikipedia's  hegemony  over search results. The sources cited in Wikipedia, many of which are original sources, will no longer get credit for their appearance there, which should cause at least a little downward pressure in their own search rankings (hence providing a little more upward pressure, relatively speaking, for Wikipedia's articles). Although the no-follow move is certainly understandable from a spam-fighting perspective, it turns Wikipedia into something of a black hole on the Net. It sucks up vast