Will Wikipedia face the same fate of the Open Directory Project -- where marketeers have spammed the site to render it useless. That's the view of Law professor Eric Goldman in a recent blog post in which he predicts the site's demise by 2010 unless it fundamentally changes its editorial process to become much less open.
As Wikipedia traffic grows, it becomes a juicier target for marketers seeking to promote themselves... Wikipedians are the only thing stopping those marketers from modifying Wikipedia's open-access pages in ways that might degrade the user experience. Wikipedians, in turn, will fight the marketers because of their pride in the site. However, as marketers become more determined and use automated tools to mount their attacks, Wikipedians will progressively find themselves spending more time combating the marketers.
He then goes onto describe a scenario where Wikipedians will tire of this upwards struggle and "decide to invest their time elsewhere":
As some Wikipedians check out, the remaining Wikipedians will have to pick up the load. With fewer hands, the site will get progressively junkier, which will reduce the pride incentive of the remaining Wikipedians, further accelerating their check-out rate. Thus, Wikipedia will enter a death spiral where the rate of junkiness will increase rapidly until the site becomes a wasteland.
The only way to "prevent this death spiral", Goldman argues, is for Wikipedia to abandon its "core open-access architecture" -- which in my mind would effectively kill Wikipedia dead anyway.
Meanwhile, Search Engine Journal is reporting on a recent change made by Wikipedia which will help to combat spammers who add links to the site in the hope of increasing their page-rank:
As of now are all outbound links from the english Wikipedia Site using the NOFOLLOW attribute, no exceptions.
No matter where you place it, Article Page, Talk Page, User Page, Project Page, whatever. No Link will get any credit at the major search engines.
This will not eliminate SPAM at Wikipedia, but it will over time certainly reduce it a bit. Especially the spam of invisible pages that have virtually no traffic but at least some PageRank is now virtually a waste of time for any spammer.
Related post: Wikiseek launches (a “better” way to search Wikipedia)