<div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">It sounds like REST is an entirely functional concept, just like all batch programming. I doubt its investors understand this but one never knows. -- Matthias</blockquote></div>Yep, as any other RPC is. REST is enabling a web-command-line style applications and is simple, the flexibility is limited to your URI to code decoding strategy - from simple case style callbacks to treating it as a module language(in plt speak) XML RPC helps with having well-defined and documented, heavier web-services SOAP+friends are the elephant herd of the bunch, can be useful in large deployments, especially with web-service discovery. In the past I found it easier to implement my own discovery mechanisms suitable for the problem domain, but I never had to integrate those to an existing infrastructure, so I might have been lucky.