"On one side, we have the people who believe that WS-* specifications such as SOAP and WS-Security will eventually dominate. And on the other, we have people who believe that HTTP with plain old XML (POX) will outlast the new contender.
I am announcing that the war is now over, whether the participants realize it yet or not. Niether side won; but they have established clear territory for themselves and will soon be giving up on taking over one another’s territory. The WS-* stack is about deep enterprise integration. […] HTTP + POX is about "reach integration". […]
If I write a big chunk of code and you tell me that only other enterprise architects can integrate with it, I might ask why. I might ask, "why is it so easy to integrate with Flickr; what development suite did they use?""
After POJOs in reaction to the overly complex EJB, here comes POX to talk about XML without SOAP. There’s some irony to see the emergence of "Plain Old" subsets within technologies that were supposed to be simple in the first place, and which are a decade (or less) old anyway.
03/18/05 update: Adwords API blog: Lessons learned launching a web service on REST vs. SOAP (Dare Obasanjo’s notes, see also ETech 2005 Trip Report: “Just” Use HTTP).