I believe the freakonomics blog was started after the book was published. The blog was a spin off from the book, not the other way around.
That was precisely my point. After the book gets published, the wiki and the blog will get popular. People, who are successful in other fields and who have got interested in x-rationality will have a background to understand posts better and will contribute to better discussions.
This has been discussed some, but I don't think it's been the sole subject of a top-level post. I want to find out other people's ideas rather than driving the discussion into my ideas, so I'm asking the question in a very general form, and holding off on my own answers: