This. REpresentional State Transfer stands in opposition to Remote Procedure Calls - except for a very narrow subset of hypertext/hypermedia applications.

The part I find most interesting about Fielding's thesis[1] is the introduction with architectural overview. He managed to map out modern Web apps perfectly - they can be REST (Web app with db/storage backend, perhaps extended with something like webdav) which is amenable to multilevel caching, smart client;movable data: json api js app, or smart client;movable code: js/Ajax - executing js delivered by server on client (subtly different from a "pure" js/json app (which is similar to an XML/xslt App).

I don't know why the hype of rest lead people to insist on conflating their architectures.

[1] http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm