REST

HTTP, not RPC

REpresentational State Transfer A fancy name for the exchange of information most developers are familiar with as HTTP, the acronym describes the passing of information about the current state of the resource identified by a particular URI.
Few verbs GET, POST, PUT, and DELETE are the "approved" verbs of REST, though HEAD (a GET without a body) is getting more discussion lately.
Infinite nouns URIs provide the nouns for REST, including URIs which don't necessarily use HTTP.
HTTP not entirely popular There are a lot of people who'd like to see HTTP used primarily for hypertext, it's original purpose. RFC 3205 suggests a lot of reasons why using HTTP as a substrate for other protocols is problematic, though it also suggests ways to do it well. More recently, Don Box, now of Microsoft, has suggested that HTTP is not the best foundation for Web Services. Microsoft seems to be pushing DIME at the moment.