Microsoft and IBM is about to release the latest spec in the WS series called WS-User Profiling (WS-UP) which address the need to associate user profile information with a web service transaction.  A use case example in the spec will show how urgency information, extracted from a user's calendar database and inserted into SOAP requests, can be used by a travel agency to intelligently price airline tickets.  More urgent the user is, higher the price.

I think WS-UP will enable merchants to provide personalized service to online customers, something that only meatspace merchants could provide until now.  Charging some customers more than others is an old art of trade that is sadly disappearing with the emergence of e-commerce.  With WS-UP, that art of trade will live on.