I've seen a lot of claims that there is something fundamentally new about service-oriented architectures. I don't buy it. Distributed computing has always been about the same set of problems. The speed of light is fixed, bandwidth is finite, and networks can be relied on to fail periodically. What we discovered in the 80's and 90's is that it's hard to build a completely general-purpose system that deals with these issues. Service oriented architecture is all about solving these problems in the context of a specific set of domain objects and business needs; that is, defining restrictions which make a viable solution easier to create. But SOA is no more a silver bullet than the approaches which preceded it, and the fundamental techniques and strategies used for the previous generations of distributed systems are the foundation of a well-designed SOA.