Have you considered Mozilla Persona? https://voo.st is pretty successfully using Facebook and Persona together for auth, at least the last I heard from them.

You should be able to get it integrated in an hour or so, and I'd be happy to double-check your code (or submit a pull request myself) if you'd like.

Thanks! I really like what you've done with QuoteRed; it's refreshingly simple and straightforward. I save a ton of quotes/articles all the time, and you've got an interface that lends itself very nicely to this problem.