"Persona" is the name of an identity system for the Web, developed by Mozilla. Persona is built around the principle that users should be able to control what personal information they share and who they share it with.
The foundation of Persona is the BrowserID protocol, which enables users to sign into web sites using their email address. In the future Persona will enable users to create a personal profile so they can easily and safely share their personal information.
To learn more about Persona see the Mozilla Persona page. To learn about the technical details of the BrowserID protocol, either to integrate BrowserID into your web site or to help out with the project itself, see the BrowserID page.