I've been working on a literature review of wikis in education, and so I've been kind of watching new developments in the news. I found this article interesting.
One of the problems (although it's a minor problem in an active wiki community) is vandalism. Somebody comes in and deletes text, adds inaccurate text, or swaps pictures. Easily undone, but it can still can be an annoyance.
But now the idea is that every change must be ratified by users. Depending on how they set it up, it could be nice. I don't think a minor edit should have to have as many ratifications as say, changing out all of the images, but it's still an interesting idea. Although you would need an active community to make this happen, and if you have an active community to begin with, vandalism is not really a problem.
Still, interesting idea.