Windows Phone Access Control
With the Access controls, you can use various social media authentication capability to authenticate their own applications. The main scenario for the control is to provide an application a way to let users log-in with their existing Facebook, Twitter, Gmail or Live ID credentials.
The control implements the oAuth 1.0x protocol for Twitter and oAuth 2.0 protocol for Facebook, Gmail and Live ID, providing a way to retrieve additional user-data at log-in time. You can also use the returned Authentication Token to make subsequent calls to each service, using the service’s specific APIs.
You can use the authentication provider you want directly or you can use the control to prompt the user for which supported provider to use.