“Real” REST APIs?

The other day I was re-reading a summary of the REST thesis of Roy Flemming and some of the constraints he exposed here. And I was wondering, how many of you actually create "real" REST APIs?

Especially this bit:

A REST API should be entered with no prior knowledge beyond the initial URI (bookmark) and set of standardized media types that are appropriate for the intended audience (i.e., expected to be understood by any client that might use the API). From that point on, all application state transitions must be driven by client selection of server-provided choices that are present in the received representations or implied by the user’s manipulation of those representations. The transitions may be determined (or limited by) the client’s knowledge of media types and resource communication mechanisms, both of which may be improved on-the-fly (e.g., code-on-demand). [Failure here implies that out-of-band information is driving interaction instead of hypertext.]

I can see the advantage of using hypertext for decoupling the client and server, especially by avoiding the creation of URLs on the client-side. But I must be honest, I never did that and except for very few examples here and there I have yet to encounter APIs offering this.

So I was wondering, how many among my fellow software developers have implemented REST properly?