Tim Bray wrote:
?Don?t do anything. ?SOA? may have meant something once but it?s just vendor bullshit now.? Looking back, what happened was, certain software architects were uncomfortable with the framing that goes with the words ?Web Services?; maybe because people think anything with ?Web? in the name should be simple and lightweight and easy to set up. Thus SOA, which is so much more Enterprisey. Me, I want to go the other way. The crucial point is that Web-like things should be simple and lightweight and easy to set up; so I think the ?Web? part of ?Web Services? is more important than the ?Services? part. SOA isn?t the future, Web style is.

* For some SOA is about exposing software through web services. This crowd further sub-divides into those that expect the various WS-* standards and those that will accept any form of XML over http (and maybe not even XML).
* For some SOA implies an architecture where applications disappear. Instead you have core services that supply business functionality and data separated by UI aggregators that apply presentations that aggregate together the stuff that core services provide.
* For some SOA is about allowing systems to communicate over some form of standard structure (usually XML based) with other applications. In it's worse form this is "CORBA with angle brackets". In more sophisticated forms this involves coming up with some form of standard backbone for an organization and getting applications to work with this. This backbone may or may not involve http.
* For some SOA is all about using (mostly) asynchronous messaging to transfer documents between different systems. Essentially this is EAI without all the expensive EAI vendors locking you in.