I find this reputation rating feature interesting. The ebay feedback system is supposed to work in a similar fashion as well, but as many have noted, the ebay thing gets manipulated a bit. Sci Fi and Cyberpunk writers like William Gibson and Bruce Stirling have been talking about this stuff for years and referring to it as stuff like a confidence server, where in a very networked world, your reputation was stored on a server somewhere for all to look at. Certainly credit card authorization centers, ATM networks and DNS authentication servers do this job to some extent, and try to establish that you are who you say you are. But those types of services are well regulated and accountable, and they usually aren't based on opinions, just math.
It's an interesting phenomena and on the surface seems like it could be good, however, if you read a little George Orwell, the implications can be quite serious. I'm not really sure I approve of it.
John