Features, Properties, and Policy - oh my! (5:20:53 PM) 
Here's another attempt at explaining SOAP 1.2's "features and properties" extensibility model in what I hope is a clear fashion. There's obviously a lot of overlap with WS-Policy, and I'd like to resolve the two in a harmonious fashion (hi Don!). Clearly, there are a bunch of us who want to do things like express guidelines and/or requirements for web service interactions, things which go beyond strictly what's in the SOAP body, in WSDL documents. Since the semantics of such things are unbounded (that's why they call it "extensibility"), some mechanism where you tag these things with names so that you can reason about them seems like the way to go. Both F&P and Policy do that. In the SOAP 1.2 Transport Binding Task Force, we came up with the F&P mechanism to allow for the fact that sometimes a given abstract semantic ("secure channel", say, or "request-response") is implemented for you via a binding (e.g. an HTTPS binding is natively secure), and other times you might use SOAP extensions (like WS-Security) to get the exact same functionality. Policy, and more importantly the specs that have been written in the WS-* space around it, does not seem to allow for that, and that's one of the things that's got me a little concerned.
Anyway, check it out, y'all. Is it really that hard to grok?
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