WS-Fed
WS-Federation (Web Services Federation) is an Identity Federation specification
WS-Federation defines mechanisms for allowing different security realms to broker information on identities, identity attributes and authentication. WS-Federation focuses on federated identity and trusting authentication tokens across different realms, privileged password management is concerned with the security, control, and audit of high-risk account passwords within an IT environment
WS-Fed will only be used with Exchange and a few other applications.