Wikipedia is a great repository of information for a net user. It exemplified the wonderful aspects of the web by being a collaborative, self-enforced online encyclopedia. SEOs know the value of an authoritative link from an authoritative site. Being a high traffic, authoritative site which allows anyone to edit its pages, Wikipedia became prone to spam links.
Not surprisingly, Wikipedia has gone the way of putting the NOFOLLOW tag on ALL of its outbound links with no exception. While this may curb some of the spamming, I don’t believe that it’ll ever put a stop to all of it. The nofollow tag is supported by Google but Yahoo, MSN Live, and Ask treat it differently. As long as links give significant weight to rankings, spammers will continue to spam.
Personally, I believe the self-policing nature of the Wikipedia should take care of most of the spam and this move isn’t really necessary. Spam aside, there are some great external links within the Wikipedia and it’s a shame that the links won’t count for much in Google.