In an attempt to limit/reduce linkspam, Wikipedia has implemented a nofollow attribute to all external links.
Essentially what this does is tell the search engines to ignore that link.
Because of its high Google PageRank and fabulous reputation with the search engines, Wikipedia has positioned itself inadvertently as the hotspot for link building and linkspam. With these credentials, who wouldn’t want a backlink from Wikipedia?
A Wikipedia page has been developed to help explain the change – because as you can imagine, there are a lot of people concerned or just plain up in arms about this. Arguments against the nofollow attribute seem to revolve around/stem from the following arguments, which can be found at Wikipedia talk:Nofollow:
… linkspam can be quickly removed. The bot made 67 spam edits in 10 hours, and a spam URL remained in the article (PHP) for hours despite reversion, because an early reversion was not fully done and later reversions just reverted to it.
….spammers will be undeterred by “nofollow”. Unsophisticated spammers who add links manually might not be aware of “nofollow”, but the operator of a sophisticated bot that constantly switches domains and IPs would probably be knowledgeable enough to be deterred by “nofollow” if he had known that we had implemented it only a few week earlier.
And some that agree that the nofollow is the way to go…
Wikipedia is a big target, and provides a big payoff for spammers when they manage to get a link hosted….Wikipedia is the single largest wiki out there (or if you count the languages as separate wikis, it’s the largest three wikis and eight of the top ten). With nofollow active, linkspammers should quickly get the idea that wikis aren’t a good place to target….
It’s an ever debated topic and everyone has an opinion or thought on the matter, including Matt Cutts. In an interview with SEOMoz, Cutts states that in a perfect world,
….Wikipedia would add nofollow to their untrusted links, but work out ways to allow trusted links to remove the nofollow attribute.
Overall, the consensus is that Wikipedia should remove the nofollow tagging and revitalize their fight against linkspam with other, more specific tools like blacklists, spam guards, and IP blocking to name a few. Most believe that the spammers will continue to add illegitimate links, either unaware of the nofollow or disinterested in what it might mean for their efforts.
Having gone back and forth on this issue for quite some time now, Wikipedia’s decision to implement this tag obviously comes with some repercussions – instead of punishing just the “bad links” they are also stripping legitimate links of the much-stressed link popularity, the main determinant in PageRank.