Why wiki works:

 * any and all information can be deleted by anyone. Wiki pages represent nothing but discussion and consensus because it's much easier to delete flames, spam and trivia than to indulge them. What remains is naturally meaningful.

 * anyone can play. 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 any 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 TV watchers. If it doesn't appeal, they don't participate, which leaves those of us who read and write to get on with rational discourse.

 * wiki is far from real time. Folk 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.

See http://www.c2.com/cgi/wiki?WhyWikiWorks for more.

----

So that's it - insecure, indiscriminate, user-hostile, slow, and full of difficult, nit-picking people. Any other online community would count each of these strengths as a terrible flaw. Perhaps wiki works because the other online communities don't. --PeterMerel