Consuming RESTful Services
If you have a Twitter account or a Facebook account, when you use their mobile applications you are consuming their services via a REST API.
Representational State Transfer (REST) defines an architecture, not a protocol, for designing Web services that consume system resources. It defines how the resource states are accessed and transferred over HTTP.
The key features of REST Web services are:
There are four HTTP methods, GET, PUT, POST and DELETE. These methods are defined by the HTTP protocol.