Principles of SOA

1. Dynamic Services replace Static Components -- WSDL provides of describing the services one is providing for thus providing a kindoff semantic inteoperability( in the technical sense atleast).
2. Service Exposure and Reflection replaces traditional System Integration -- As some survey rightly pointed out 60% of money today is spent on System integration. With SOA`s the tiny-miny granularity of webServices will save millions of the enterprrise dollars.
3. Coding for broad Applicability supersedes coding for reuse -- Instead of providing interfaces only for java compatibility to spped up applications services will now have multiple interfaces with the primary being for SOAP based bindings to ensure compatibilty with all providers and consumers.
4. Ad Hoc upgrades supplant Disruptive Upgrades -- Due to dynamicity in both the service descriptions and there invocations(WSIF) real time upgraddes are something in the near future.
5. Scalability handled Bottom-Up instead of Top-Bottom -- This by far i think is the most important advatage. Remmember in the RISC vs CISC case, CISC won. These guys should have realised this a lot earlier.
6. Platform dependance gives way to Platform irrevelalnce -- using the 3 corner stones spawned via XML - WSDL, SOAP and UDDI we have finally reached a stage where we can talk about platform independance.
7. Fedaration model of software replaces disctatorship model -- due to the high degree of loose coupling possible it will be no longer possible to enjoy a monoloy because of the complexety involved.