Now I know what an ESB is :-)

This is what I got to read from "Andreas Mueller" on this thread
http://www.theserverside.com/user/userthreads.tss?user_id=13939

What they mean is just a form of workflow, based on P2P. A service is listening on an input queue, processes a message, does some generic or specific transformation, calls an EIS or a Web Service, generates an output message and sends it to another queue which is input of another service and so on. So in fact, this is just plain workflow, based on messaging. The 'bus' is a logical term of a messaging infrastructure, connected by routing connections. It's just the ability to address queues, located wherever.