Re: A decade ago we would have been listening to the same guff about SOAP/XML.
REST is an architectural composition of services.
The idea is simply to overlay one interactions over an application layer protocol, to avoid explicitly writing business logic when it can be defined in terms of the protocol.
RPC is just marshalling -> addressing -> unmarshalling -> processing -> marshalling.
You can do RPC over HTTP but you really shouldn't.
These do the same thing but in the RPC example I get to write all the code and the logic, in the REST example, it comes for free by virtue of layering my application concern "Chat rooms live on separate nodes" over the redirect status codes offered by HTTP, and make sure that my identifiers are URI.
This adds a side benefit in that in the REST case, redirects are cachable so my application is more network friendly.
Example: Chat rooms. (RPC)
(C) >> (S) "Find Room1"
(C) << (S) "Room1 is at 188.8.131.52"
(C) >> (Room1) Join
(C) << (Room1) Welcome to Room1
Example: Chat rooms. (REST)
(C) >> (S)
GET /rooms/room1 HTTP/1.0
(C) << (S)
301 http://184.108.40.206/room1 HTTP/1.0
(C) >> (S)
GET http://220.127.116.11/room1 HTTP/1.0
(C) << (Room1)
Welcome to Room1