I admire Mozilla's openness, and the existence of TFA is an example of that, but in this case it amounts to really poor communication with the rest of the world. Why all the past tenses? Would it have killed anyone to say "What does Persona get right?" or "Why has Persona failed to gain wide adoption so far?"

The whole attitude here is bizarre. It seems Persona is supposed to have taken over the world by now, while in reality it's not clear that it's even in beta, let alone out of it. E.g., we're supposed to get the javascript lib from one place only, because we're warned that the protocol could change in breaking ways at any time. Let's get to version 1.0 before complaining that facebook hasn't been driven out of business!

I support the recommendations to simplify and get rid of sessions.