Nature “cooked” its article on Wikipedia, the Encyclopaedia Britannica has claimed. It’s worth noting that The Register, which hosts the linked article, isn’t a bastion of balanced journalism (and often contains anti-web 2.0 invective), but it certainly sounds like something fishy may have been going on. At the end of page 2 there’s the full text of Britannica’s original complaint, which may help you decide.
Personally, I’ll tell you the truth: I’m not that fond of public wikis. They certainly have their uses in intranets and small groups (I actually think a fully-featured wiki can serve as a useful intranet all on its own), but when you invite the general public to edit a site you’re letting yourself in for a world of hurt. Or at least, a world of spam, ego-boosting, competition-eliminating and dodginess.
Although the theory of public editing is sound for articles that lots of people know something about, factual accuracy diminishes for more obscure topics, purely because if something is wrong it’s likely to take longer