If you haven't seen Pete Lacey's socratic dialogue on the evolution of SOAP then please go and read it straight away. An excerpt to whet your whistle:
Dev: Okay, whereâ€™s the spec on this?
SG: Oh, there is no spec. This is just what Microsoft seems to be doing. Looked like a good idea, so now all the cool kids are doing it. However, there is this new thing. I think youâ€™re gonna like it. Itâ€™s called the Web Services Interoperability Group, or the WS-I. What theyâ€™re doing is trying to remove a lot of the ambiguity in the SOAP and WSDL specs. I know how you like specs.
Dev: So, in other words, the specs were so bad you need a standards body to standardize the standards. Lord. Well, will this solve my interoperability problems?
SG: Oh, yeah. So long as you use a WS-I compliant SOAP stack, avoid using 8/10ths of XML Schema, donâ€™t use any unusual data types, and donâ€™t count on working with WebSphere and Apache Axis.
There must be something in the air because Duncan Cragg has also written some fun and informative articles in the same style for a new series called the REST dialogues: Getting Data and Setting Data. If you want to get a better view of what it means to be resource-oriented then this series looks to be the business.