Please take a look at what Ganesh has to say about the principle of the "Viewpoint Flip" and how it enables you to better approach the design of services (let's not use 'SOA' too much in this context...): crisp and all-there-is-to-say. My opinion in the past few years always has been that object-oriented thinking is way misleading, to say the least, when trying to grok services: we needs to switch our viewpoint, our thinking to be *service-oriented* (take that literal). BTW: an approach like this and tooling made explicitly for this approach may help you with flipping your viewpoint. Read More...