In response to: Cloud - SOA = ZeroI think you've made a very good point here. A lot of the focus of cloud computing is deploying an entire app on a public cloud so that it can be accessed from anywhere on the Internet/Web and so that the app owner doesn't have to host it on his own equipment. Even in this scenario, I think it makes sense to design the app as an SOA for all the reasons that SOA generally makes for better business apps than a traditional monolithic layered architecture (a.k.a. enterprise application architecture) has. But an equally important approach which I think is a lot less recognized is that individual SOA services can be deployed to public and private clouds, making them easy to host and easy to access with consumer applications and composite services. When an app or composite service aggregates several services, those services don't have to be deployed in the same data center or cloud as the app, they can be deployed in various other clouds. Like I said in Intro to Cloud Computing, "cloud computing sounds like SOA and ESBs to me."