Review my side project: Sqrt(2)
tokenadult: I've thought about this for a long time. (I've been an online moderator since 1992, on a variety of networks.) I would prefer a system of testing people on specific knowledge of specific subjects, and giving them visible badges to show other users they know about, for example, economics or education policy or computer industry issues. Then use the people's knowledge badges to weight karma scoring (and introduction to moderation privileges) behind the scenes. If you program it, I and my friends will visit the site.