http://wiki.lesswrong.com/ is now live, for all our Wiki needs. The previous Wikia wiki has been imported. Knock yourself out on linking there from comments or blog posts (yes, you will have to link manually, there is no CamelCase convention yet on the blog and comments).
See here for proposed wiki usage guidelines - note that these do not yet seem to appear in the Wiki itself, hint hint.
One possible reason for favoring the wiki, at least in the long run: a well-structured wiki is more discoverable and accessible. The huge branching tree of your OB posts is daunting enough; the entire past corpus of LW is rapidly going to become even more intimidating for lacking a single author with consistent style and themes. Imagine LW at roughly the same rate of content generation and a slowly expanding user base, three years from now. Where would someone even start?
Distilling the ideas into a manageable synthesis of what's been discussed in multiple posts, with extensive inter-linking, terms defined, and links to relevant posts would be far more useful for a newcomer than just minimal definitions with links to posts.
To use an academic analogy, if LW posts are journal articles, the wiki ought to be a textbook.
We just need better scholarship in the LW posts themselves, with review articles and tutorial articles, and possibly thematic workshops.