This looks great to me, if it works as I imagine it does: use Facebook to authenticate myself to services, but don't give them any information about me - just a

This looks great to me, if it works as I imagine it does: use Facebook to authenticate myself to services, but don't give them any information about me - just an anonymous token. I want to be able to use the convenience of Facebook login, but usually I don't because I'm worried about how much data the app I'm authenticating with has access to.