Increasing user control over identity is the primary aim of Identity 2.0. Since the current state of digital identity leaving users with no control over their personal information, Open ID seeks to put users back in charge. By keeping creating an identity with one of the Identity Providers, the user is in direct control over what sites have access to his identity and for how long.
Dick Hardt’s presentation at the 2005 O’Reilly Web 2.0 Conference on Identity 2.0 is a good resource for learning more about Identity 2.0.