You can set up OpenID on your domain and then delegate authentication elsewhere or run your own authenticator. Basically similar to having email on your domain.

You can set up OpenID on your domain and then delegate authentication elsewhere or run your own authenticator. Basically similar to having email on your domain. Also Jeff mentions that this is about sites which don't have an impact on you. So you will use it for some forum but not banks nor anything your real life depends on.