Dave Taylor has a great article in April's Linux Journal titled The Failure of Wikis. He nails the underlying problems with this form of mediocre way of creating and editing content. Perhaps the funniest part of the page is, however, a reader's comment "If you still have problems I suggest you start hiring smarter people or get smarter friends." The irony is that is exactly one of the points Taylor made - that wikians think those that don't get wikis are just too dense to get it.
It is a rarity to find a wiki that comes close to being as good as a page with comments on it. Each trip I make to Wikipedia leads to much more time spent editing incomplete or inaccurate information than is gained in the gleaning of information originally sought.