In a  move that was a long time coming, Wikipedia has decided to attatch rel=nofollow to all outgoing links. This small change will mean that all links from Wikipedia will be ignored by Google (and Msn, Yahoo) when weighting how important sites are.

This will have too affects. The first is that spamming of Wikipedia will reduce dramatically, freeing up editors to spend their time increasing the quality of existing pages rather than removing spam.

The second is that some existing sites that rely heavily on honest Wikipedia articles for page rank will drop dramatically in the rankings.