I'm personally getting fed up of seeing another article, or presentation from a vendor, which equates SOA with technology. Its very like those articles in the 90s which tyalked about a technology as being "OOD". Object Oriented Design was about a shift in how people designed systems, away from process oriented design, towards placing the domain model at the centre of any system. By making the domain model of primary importance in a system meant that you modelled the data and "things" of your environment how they actually happened. This was an immensly powerful metaphor that represented a shift in the way the average system was built.
SOA is a shift in a different area, its about changing the way we think about architecture. Its complete rubbish to say that SOA is an approach that started only with Web Services, as with OOD (which started with Simula back in the 60s) SOA is a concept that has been around for quite a long time, in fact it would be fair to say that most very large IT builds have been using Services since the year dot. So if SOA is an old architectural pattern why is it more important now? I'd say for two reasons, firstly because more organisations and projects are at a level of complexity where an architecture is actually required, and secondly because it is now simpler to translate that architecture into reality.
The key message on SOA therefore always has to be that SOA is about architecture, not about technology. And the purpose of architecture is to define the framework and context for the solution, this means that it must be focused on what the people who request the system want. This means it MUST be focused on the business.