What’s a Wiki: I’ve written about wikis before, but here’s a good explanation and links to really figure it out.
Also, Don Park has been having a conversation about what separates a blog from a wiki, and when exactly does a blog entry become a wiki page? I’ve some thoughts on this, but I’ll save them another day.
My theory on wikis is that they only really work for about 5% of projects, but they can be utterly amazing for those 5%. The MT Wiki is one proof of this. Everything2 is another.