Update: Ember.SimpleAuth 0.1.0 has been released! The information in this is (partially) outdated.
With the release of Ember.SimpleAuth 0.0.4 the library is compliant with OAuth 2.0 - specifically it implements the "Resource Owner Password Credentials Grant Type" as defined in RFC 6749 (thanks adamlc for the suggestion). While this is only a minor change in terms of functionality and data flow, used headers etc. it makes everyone’s life a lot easier as instead of implementing your own server endpoints you can now utilize one of several OAuth 2.0 middlewares that already implement the spec.
October 28, 2013