Doug, anticipating my response, promptly responds.
He brings up the “identification vs. location” issue, which I agree remains a point of contention between many (though the Web wizards are all in agreement on this one, at least 8-). But we’ve already been there, and I don’t think I could explain my position much better than I did there. So I’ll concede that point for the moment so we can move on to an aspect of architecture which I feel is more important in determining the degree of loose coupling; late binding.
REST uses late binding, as REST clients are developed to a system-wide abstraction; the resource. As an example of what this enables, a RESTful client can get data from any RESTful server. SOA cannot do this; a constrained interface is required for this, whether in a RESTful manner or not.
FWIW, in these terms, one can look at REST as the natural evolution of SOAs on the Internet; SOA + late binding => REST