vBulletin 5.4.1 Alpha 4 is now available to licensed customers. This is a development release and should not be used in production environments.
The login/authorization system has been reworked to allow third-party logins beyond Facebook. This is a modular system and can be expanded via the Package system in vBulletin. This will allow sites to create custom authentication systems that fit the needs of their users. We've included Twitter OAuth as a working example of how to use the system. Users can connect their accounts to multiple third-party sites.