I gave a presentation on identity and reputation at Yahoo! today as Chad Dickerson's guest. The talk (slides) introduced user-centric identity and then introduced the reputation framework that my students built. I hope we'll have releasable code and a paper available soon. I'm looking for funding to support further development of the framework. If reputation is interesting to you or your organization, contact me. I'd be happy to talk to you about what we've done and how you might be able to participate.