[prawks]

The key is:

> [a] 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)

There is out-of-band "communication" in that the client and server agree on these media types and how to use them.

The following article does the best job I've seen at illustrating a truly RESTful service:

http://www.infoq.com/articles/webber-rest-workflow

The <next> node in the response to the order POST is one such example.

[superdude264]

Great article. If I'm understanding it correctly, it seems like the advantage comes from mapping your domain actions to the standard HTTP actions on each domain object. Once this is done, your API is simply the media types and the interaction with your service can be done through well-understood HTTP actions rather than learning a bunch of method calls as in an RPC approach. Correct?