On November 30th, 2016, Mozilla shut down the persona.org services. Persona.org and related domains will soon be taken offline.

For more information, see this guide to migrating your site away from Persona:

https://wiki.mozilla.org/Identity/Persona_Shutdown_Guidelines_for_Reliers

"Persona" vs. "BrowserID"

Persona is a complete implementation of a new, distributed login system from Mozilla.

BrowserID is the open protocol that governs how Persona works.

Common Persona Terminology

BrowserID
An open, decentralized protocol for authenticating users based on email addresses.
Identity Provider ("IdP")
Services which issue credentials to their users.
Email providers can become Identity Providers for their users by adding support for the BrowserID authentication protocol to their service. If an email provider doesn't support Persona, Mozilla operates a fallback Identity Provider at login.persona.org.
login.persona.org
A fallback Identity Provider run by the Identity team at Mozilla.
Persona
The user-facing name of a complete suite of identity-related services from Mozilla, including the Mozilla-operated fallback Identity Provider. End-users should never see the term "BrowserID."
Persona may eventually include features beyond the BrowserID protocol, such as parts of Firefox Sync or a dashboard for Open Web Apps.
Relying Party ("RP")
Any website, application, or service that allows users to log in via Persona.

Project Codenames

BigTent
A suite of three fallback Identity Providers that vouch for users of Hotmail, Gmail, and Yahoo Mail respectively. BigTent operates by bridging the BrowserID protocol with OpenID or OAuth for each email provider. Source available at https://github.com/mozilla/browserid-bigtent.
Vinz Clortho
An Identity Provider for @mozilla.com and @mozilla.org email addresses. Operates by consulting LDAP. Source available at https://github.com/mozilla/vinz-clortho. The name is a reference to the 1984 film Ghostbusters.

Uncommon Persona Terminology

Primary Authority ("Primary")
Deprecated term for email providers who are also able to act as Identity Providers.
Secondary Authority ("Secondary)
Deprecated term for a fallback Identity Providers who can vouch for users whose email providers aren't Identity Providers. Mozilla operates a fallback Identity Provider at login.persona.org.
Verified Email Protocol
An old, defunct name for the BrowserID protocol.