#ReST
Hypermedia as the Engine of Application State (HATEOAS)
https://blogs.oracle.com/craigmcc/entry/why_hateoas
http://kenai.com/projects/suncloudapis/pages/HelloCloud
Github API looks restful. see https://api.github.com
How popular API's are versioned: http://www.lexicalscope.com/blog/2012/03/12/how-are-rest-apis-versioned/