I wanted to refresh my understanding of Microsoft's Web Services Enhancements (WSE) 2.0, so I started reading an old article by Aaron Skonnard. It's really nice. I particularly liked the second paragraph:

"The popularity of the WebMethod framework and others like it has nearly convinced mainstream developers that Web Services are only useful for RPC over HTTP. The irony is that some of the most interesting and powerful Web Services of the future probably won't use either. The Web Services concept is designed around XML messaging over arbitrary transports. XML messaging applications can benefit from a variety of different communications protocols as long as they aren't detrimental to the fundamental interoperability goals of the system."

Web Services are treated by many as the modern way of doing RPC over XML or even as the "interoperable" way of doing distributed objects using angle brackets. Of course they could be used like that and in fact they are (OGSI, WS-RF). However, Web Services are more than that. They are all about message exchanges and interaction patterns.

Just my 2p.