Why is it called "Representation State Transfer"?
http://www.boeing.com/aircraft/747
The Client references a Web resource using a URL. A representation
of the resource is returned (in this case as an HTML document).
The representation (e.g., Boeing747.html) places the client application in
a state. The result of the client traversing a hyperlink in Boeing747.html
is another resource is accessed. The new representation places the client
application into yet another state. Thus, the client application changes (transfers)
state with each resource representation --> Representation State Transfer!