Mozilla has introduced Personas, a project formerly called BrowserID. It is a multi-browser website authentication mechanism that is similar to Facebook Connect. The procedures set up by Personas allow users to login to websites that support their BrowserID signing and avoid lengthy verification processes.
"The Persona name resonates with the idea of personhood as well as online identity as a facet of our lives, and therefore strongly tied to user identity. We’re very excited about this new name and the new features our identity system will offer. Some of the things we’re planning: an identity dashboard, user data interconnect features, and more."
What about the old Firefox Personas?
"For the past few years, many Firefox users have enjoyed “Personas”—a quick and fun way to theme the background of the Firefox toolbar. The Addons team blogged about changing their name a couple of weeks ago. No doubt there will be some confusion during this transition, so if you have ideas for how to make the transition smoother, definitely let us know! We believe the long-term value of the Persona name will far outlast the short-term discomfort of change."
Mozilla demonstrated the use of the thing back when it was still called BrowserID in this video.