Regarding the definition and understanding of SOA, all parties people speak. From the history of software engineering, it is a natural evolution of methodology method, which is a new architecture style. SOA is based on many technologies, such as Web Service, HTTP, XML, Disitributed Computing, ESB, etc.
SOA highlights business and IT Alignment, Open Standard, focus on Software Parts Flexibility (RESUILITY). SOA can only fully reflect its value in the enterprise architecture.
Another Jason Weisser, one of the IBM SOA's nasal ancestors, has a brilliant insights in a talk. I agree. Here is URL LINK.
http://news.9cbs.net/n/20060406/89125.html
