Stuart Charlton says stuff about Building a RESTful Hypermedia Agent, Part 1:
Building a hypermedia-aware client is rather different from building a typical client in a client/server system. It may not be immediately intuitive. But, I believe the notions are rooted in (quite literally) decades of experience in other computing domains that are agent-oriented. Game behaviour engines, control systems, reactive or event-driven systems all have been developed with this programming approach in mind.
He points to a diagram from Artifical Intelligence: A Modern Approach 1 and adapts it to the RESTful web. Agent sensors become HTTP's "safe" methods (GET), effectors the "unsafe" methods (POST, PUT, DELETE). The HTTP protocol and content type definitions make up the agent's model of the evolving, mutable state of its environment (the web). I'm enjoying thinking about RESTful client-server interactions on the web in these well-reasoned terms. The REST style, to me, is all about enabling software agents. Not just web browsers or search index crawlers, but agents that might mine your texts, geocode your news, or ETL your spatial data (and wash your socks). I'm looking forward to the next installment.
S.J. Russell and P. Norvig, Artificial Intelligence, Prentice Hall, 2009.