From Microsoft:

“Organizations creating, managing, and using Web services will often need to state their privacy policies and require that incoming requests make claims about the senders' adherence to these policies.

By using a combination of WS-Policy, WS-Security, and WS-Trust, organizations can state and indicate conformance to stated privacy policies. This specification will describe a model for how a privacy language may be embedded into WS-Policy descriptions and how WS-Security may be used to associate privacy claims with a message. Finally, this specification will describe how WS-Trust mechanisms can be used to evaluate these privacy claims for both user preferences and organizational practice claims.”