A wiki is a great collaboration tool. Everybody knows Wikipedia, but before Wikipedia, there was the first-ever, one-of-a-kind, original wiki. The original wiki is quite different from Wikipedia, though it was in fact the original inspiration for how to help people to collaborate effectively on an online encyclopedia. While Wikipedia attempts to produce a comprehensive document, and so requires many rules (such as the neutral point of view) and processes to achieve this goal, the original wiki is more like a continuous brainstorming session—a wiki about concepts and ideas. If Wikipedia is a document wiki, then the original wiki is a concept wiki.
This wiki, i.e. this wiki right here that you're looking at, is the Atheism United wiki. At least initially, this wiki will function best as a concept wiki, where new ideas are okay to try out, there aren't so many strict rules about who can edit what and when, and people can be much more free to express many points of view individually.