Interesting discussion to have. I think it is a little bit like Esperanto, the makeup language that IF the whole world was to learn and use that uniform language, it would be so beneficial. Internet users probably don't need another place to sign up with a new set of username and password, so the concept of Open ID is really great. There is also some incentive for website owners (less friction), but if it ultimately means that only a few Google, Yahoo,... own all user identities, will that be the right solution?