In principle, a wiki is for whatever its users want it to be for. The format lends itself to collaboration--but collaboration that involves anyone at all, who can do anything they want to the pages. You might think that this leads to disruption.
The idea is that anyone can share the knowledge they have with anyone else!
Why wiki works:
- any and all information can be deleted by anyone. Wiki pages eventually represent nothing but intelligent discussion and informed consensus because it's so much easier to delete flames, spam and trivia than to indulge them. What remains is naturally meaningful.
- anyone can play and have fun. This sounds like a recipe for low signal - surely wiki gets hit by the unwashed masses as often as any other site. But to make any sort of impact on wiki you need to be able to generate content. So anyone can play, but only good players have a desire to keep playing.
- wiki is not WYSIWYG. It's an intelligence test of sorts to be able to edit a wiki page. It's not rocket science, but it doesn't appeal to the TvBabies. If it doesn't appeal, they don't participate, which leaves those of us who read and write to get on with rational discourse.
- Folks have time to think, often days or weeks, before they follow up some wiki page. So what people write is well-considered.
- wiki participants are, by nature, a pedantic, ornery, and unreasonable bunch. So there's a camaraderie here we seldom see outside of our professional contacts.
... and it's often fun. And we all know people play nice when the game is fun.
So that's it - insecure, indiscriminate, user-hostile, slow, full of difficult, nit-picking people, and frivolous. Any other online community would count each of these strengths as a terrible flaw. Perhaps wiki works because the other online communities don't. :)