Some context: we just finished proving out OpenID Connect as a reasonable protocol for websites (seriously, there's good stuff hiding in there) and are now working on rewriting the prototypes so that they're stable and worthy of trusting. Expect an announcement in the next month, along with better documentation and on-ramps for contributors.
I think it's a real shame about Mozilla Persona... Anyone know why it was dropped, it was always going to be one of those things that the people/organisation running it had to be in for the long term.
We never got Persona past the point of needing an external script on websites pointing to the Persona domain. We really don't want to risk anyone getting XSS'd or assume transitive trust in whomever would follow Mozilla in custodianship of the domain, so we plan to kill the service, destroy all user data, and maintain ownership of the domain for many years.
Also, Persona was pretty explicitly designed in a way that assumed eventual, native integration into browsers. IMHO, any successor without the backing of a browser vendor would be better served by starting from scratch with a different set of assumptions. :)
What about a browser plugin? Perhaps support could be added through browser plugin, without explicit support of browser vendors. Then when adoption is significant enough, perhaps browser vendors will get on board.
(Hypothetical future in which Persona takes off. I think it's a great idea.)
https://github.com/letsauth/letsauth.github.io
It's a successor to Mozilla Persona in development.
Details in the readme and on freenode #letsauth (mirrored to gitter.im/letsauth/letsauth).