“[...] we could make Twitter the open identity system we’ve been looking for. Make your Twitter ID the one that you use to log on to other service [...]“
- Ability to associate an existing account with an OpenID
- Ability to switch to another OpenID (sort of a password recovery for OpenID)
- Ability to create a new account directly with an external (non Twitter) OpenID (be a standard relaying party)
If they want to, they can also be an OpenID provider (which should be good for them, of course ;-) ).