Mozilla Persona is a way to sign into websites that works with any email address.
Today, Mozilla announced a new Persona Identity Bridge for Gmail users. This means that every Gmail user can now sign into Persona-powered websites with just a few clicks using their existing account credentials. No new password required.
Combined with Mozilla's Identity Bridge for Yahoo, Persona now natively supports more than 700,000,000 active email users. That covers roughly 60-80% of people on most North American websites.
The Gmail bridge is available now, and all Persona-enabled sites will automatically use it. You can try it right now by signing into Webmaker
Mozilla said that Gmail users can sign into sites with Persona, but Google can't track which sites they sign into.