My post the other day about creating an XMPP based unified cloud interface has generated a lot of interest (Thank you Dave @ Cnet). One point that has been mentioned by several people is in regards to the proposed usage of a XML schema and whether a predefined model makes any sense. A few of you also said to look at a more "RESTful" architecture, which in my opinion is not mutually exclusive to a XML schema. Several have pointed me to the SNMP protocol and its object model, as a good example. SNMP uses a strict verb discipline in tandem to the protocol's small operator set, and the 'resources' are addressed with a uniform global scheme of Object identifiers.
Yet another suggestion was to look at the Resource Description Framework (RDF) as the basis for UCI. What I find interesting about the RDF data model is it based upon the idea of making statements about Web resources in the form of subject-predicate-object expressions. I also found it's use of statement reification and context possibly very useful. Although RDF brings us back to the usage of schemas.
So I'd like to propose a question. If not a traditional XML Schema, what other approaches may give us equal or greater flexibility?
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