Changes

* [https://rpxnow.com/ RPX/Janrain Engage] is similar; we should consider how what we does relates to that (and to [https://rpxnow.com/docs their API]) * [http://en.wikipedia.org/wiki/OpenID OpenID on Wikipedia], as some basic background * [http://softwareas.com/oauth-openid-youre-barking-up-the-wrong-tree-if-you-think-theyre-the-same-thing OAuth vs OpenID]