Nick Gall comments on the Gartner WOA report which he co-authored. The report starts by defining WOA; as an extension of Roy Fielding’s definition RESTful architectures, with respect to the four uniform interface constraints in particular.
The key take-away from the report is that the application neutrality constraint is a fundamentally important constraint; and when applied to an SOA, it allows for global network effects in terms of serendipitous reuse.
According to Nick, the Gartner report is a result of consensus between Anthony Bradley, Dan Sholler and himself and represents Gartners position on WOA in relation to the WS-* specifications.
The report notes that
The primary problem with the specifications known as WS-* (such as SOAP, WSDL and UDDI) is that their principal emphasis is on implementation neutrality. […] Although this is not an unworthy goal […] it shifts the focus from the generic interface constraint of application neutrality.
Application neutrality should be the principal goal of an interface, because it is precisely this characteristic that enables shareability (a fundamental SOA principle).
The key to shared use (reuse) is a generic, application-neutral protocol, such as the Atom Publishing Protocol (APP) or Google’s GData Protocol. Conversely, the more application-specific a protocol is, the less shareable it is.
Nick concludes by quoting the report "The goal is to focus on the key generic interface constraints that unite these [REST, WOA, Web Services] concepts, not debate the nuanced differences among them."; which he believes is what will put the power of the “Web” back in “Web Services”. The report is available in the Gartner web-site.