A federated identity can be used to provide a single sign on to multiple applications, both in the enterprise and in the cloud.
Even though the platform follows WS-Federation, an identity-management standard supported by the likes of IBM, Verisign and CA, Microsoft's implementation of a claims-based architecture is its own variation on the specifications. Microsoft's architecture is a more flexible approach to establishing a user's identity. Says Kim Cameron, Microsoft's chief identity architect:
In this model, developers don't have to program identity management into the application. It comes to them.