Open ID

Just discovered that stuff developped by Danga. Not sure I understand exactly how it's supposed to work.
An OpenID identity is just a URL. You can have multiple identities in the same way you can have multiple URLs. All OpenID does is provide a way to prove that you own a URL (identity). And it does this without passing around your password, your email address, or anything you don't want it to. There's no profile exchange component at all: your profiile is your identity URL, but recipients of your identity can then learn more about you from any public, semantically interesting documents linked thereunder (FOAF, RSS, Atom, vCARD, etc.).