Jon follows up his Groove/REST blog by quoting Paul and I and concluding that we are actually saying the same thing. This is a really important point, so let me emphasize it here. As I wrote privately to Jon;
If you choose your verbs such that each can be used on every identifiable thing, then you have no addressing problem.
The moment your interface includes a method which is not uniform to all things, then you lose something because some aspect of identification is removed from the identifier, and moved to the method. For example, see Dan Connolly’s report on the problems with WebDAV’s PROPFIND method, which can only be invoked on WebDAV properties. On the Web this is considered a major faux pas, but it’s commonplace – arguably a defining feature – of and with Web services.
Also, this is related to my post on generalization of application interfaces.