Today I was at FujiSoft for the OpenSocial Hackathon organized by Google. Tomomichi Ono, Robert Gravina and I implemented a rating framework (and a sample movie rating social application using this framework) based on the idea I had proposed last week.
This framework allows anybody (without any hardware) to create a social rating application for social networks. This can be book ratings, news rating, or anything that can be rated. "Social rating" means that the act of rating can be shared with friends and commented on, and in addition to the average rating you see the average rating from your friends, among others.