"If you want fixed content that people comment on, you should use a blog. If you want a dynamic, back-and-forth conversation, you should use a forum. If you want to create an authoritative single document [created by many people], you should use a wiki."
Someone from pbwiki in a comment on Wikis Still Slow to Catch on Internally, Externally
It would seem to be the growing consensus that collaborative editing and knowledge creation is the coming awesomeness. Mediawiki and similar seem able to provide all of the above modes of operation - the collaborative editing of the wiki; commenting on wiki pages, like a blog; and talk pages to provide a dedicated area for discussion. So why isn't a wiki being brought forward as a means to accomplish all the above?
I think what the first comment is saying (especially in the context of its parent article) is that wiki usage is still on the borders of most/many peoples experiences interacting with text n stuff on the internet. I think we're all very famitiar now with commenting, or to put it a bit more bluntly, adding some text to some existing text by typing into a textbox at the bottom of the page. But, Wikis are a bit different looking - the text we are given, or expected to write is leavened with [[funny looking symbols]]. Suggesting perhaps that we need some more wysiwyg editors, or time for the geeky education to make its way through our bridging capital rich friends.
I think another restricting factor at work (almost exclusively for the nuubs) is the fear that they'll mess it up somehow and not be able to fix it, and everyone will know. And call them wikitard behind their back or something. This fear is too damn common and the solution is in everyones grasp.
Its called Undo, or sometimes Revert. I know it's there, but it can't be prominent enough, in either the user interface of these tools, or in the training. The fact that one of the most powerful aspects of a wiki (ie. Wikipedia doesn't disintegrate under the weight of vandalism because it's easier to click Undo than it is to commit vandalism) is not used to combat one of the most common fears slowing adoption of this critical technology seems stupid and easily correctable.
I'd like to see Undo functionality displayed more prominently, and people being taught that it's ok - you can't break the computer. It's ok, you can't lose anything, because it saves everything automatically, And here's a private sandbox where you can play and not be criticised; and here's a page of comments you can use to experiment with writing in public, but it's ok because it's not the front page or anything, and besides it's just a comment, like a post-it note or something.
And here's the Undo button for this more important seeming stuff, and here's all the authors - y'see? it's not like they're professionals or anything.
And here's the first edit of the page. Yes, thats all. It's like polishing a stone, or improving a shared cake recipe. It doesn't have to be perfect at the start, it just gets better with time, like wine or something.
Maybe all wikis should start off with a cake recipe.