[OlavHN]

If all you want is a simple, privacy friendly login then check out Mozillas persona: https://login.persona.org/

Chances are your users won't have it already, but it's the only single sign-on solution I would use without calculating how much privacy I'm willing to "sell" for not having to register yet another time and remember yet another password.

[callahad]

Thanks! The Persona team is working hard to get past the "your users won't have it already" bit.

1. By the end of March, we'll turn on a Persona <-> Yahoo (OpenID) bridge, followed by one for Google (OpenID) and Hotmail (OAuth). Net win: A billion+ users can fully complete a first-time login with Persona using just three clicks. (Try it today! Use a Yahoo address at http://beta.123done.org/)

2. A subset of the team is working on a Persona-backed replacement for Firefox Sync. Net win: tens or hundreds of millions of additional users added to the "Persona-ready" camp.

3. The upcoming FirefoxOS phones all have Persona baked into the default Marketplace. Net win: time will only tell.

The above projects just streamline the initial onboarding experience: anyone can use Persona right now with any email address. FWIW, last time I checked, Persona's is averaging > 13,000 daily login transactions over a rolling 7-day window.

I don't want to derail, but if you have questions or need help getting Persona set up on your site, please free to email me.

[sergiosgc]

Second that. Mozilla persona is fully distributed and not owned by a single entity. Moreover, it sounds like great engineering: do just one thing and do it well.

I hope it becomes the universal single sign on of the Web.