I currently have an e-mail confirmation screen that makes it clear a new account is about to be created. I seem to remember Stack Overflow getting me to click a button too. It adds no real burden to new (non-Twitter) users.
I'm still wondering about the best way to handle this in Rails though. Passing the OAuth hash data through a second request to confirm the e-mail doesn't feel quite right to me, even if I make an OAuth service object to clean up the code and some policies to standardise the hash.
We do have bizarre situations like people logging in using Twitter or Yahoo accounts bound to GMail, but they are rarely an issue. It's more frequent the case where a user is trying to open their account page using the wrong GMail account.
Anyway, our plan is to detect multiple accounts with the same e-mail address and offer the user to merge them, but we are not sure about how to do this since e-mail addresses are not immutable.
I'm amazed there is no open-source, drop-in HTTP proxy to authorise access to REST APIs. The closest I've found is PingFederate, which is kind of expensive, and DoorMan[1], which seems incomplete and unmaintained.
Am I the only person who'd find this useful? What are other people doing - building it into their APIs?
