Hackers should pay attention to:
http://roy.gbiv.com/untangled/2008/rest-apis-must-be-hyperte...
I have also found collection+json and hypermedia application language (HAL) to be useful.
Plus, I have spent a bunch of time reading the Restful Web APIs book from O'Reilly. Useful for me, as a relative newbie, in providing some logical foundation to start from . . .