Anything wiki-like for Plone4

Question

I'm trying to figure out a way to make a document management/knowledge management portal using Plone4. We really like idea of having a Wiki as a section of our site or, better yet, as a type of document in every space but with wiki-style linking and even preferably with wiki style editing (plaintext with wiki markup, but parsed to rich html on display).

Anyway, what I'm hoping for is some pointers to documentation, extensions and/or literature.