You can now use your Google account credentials with Mozilla Persona to log in to Web sites, but have no fear: Mozilla assures its users that Google can't track which sites you use with its service.

"Persona remains committed to privacy: Gmail users can sign into sites with Persona, but Google can't track which sites they sign into," wrote the company on its Identity at Mozilla blog, which tracks Persona development.

Mozilla added Gmail support to the log-in service on Thursday. The Google support in Persona joins support for Yahoo log-ins, as well as Persona's own log-in credentials. Looking for traction to compete with social network log-ins such as Google and Facebook's Connect, but desirous of remaining respectful of user privacy, Mozilla hopes that Persona will be a password killer.

Persona works by allowing you to verify your identity through your account provider's existing OAuth or OpenID credential. The technique, which Mozilla calls Identity Bridging, skips sending you a verification e-mail.

While there aren't many site at the moment that work with Persona, Mozilla has suggested people test it by logging into its Webmaker service. Persona also fuels logins on Firefox OS phones.

"Firefox OS includes a native implementation of the Persona APIs," wrote a Mozilla spokesperson in a statement to CNET. "When you use Persona on a Firefox OS device either in an app or on a webpage, you see an interface optimized for the platform, including the ability to use identity bridges like the one announced today."

By adding Google support, Mozilla has built into Persona two of the top three Web mail providers. Only Microsoft's Outlook, originally Hotmail, is lacking for the service to work with more than one billion people. Google and Yahoo log-ins account for 70 to 80 percent of the people using North American Web sites.

Updated at 4:29 p.m. PDT with Firefox OS statement from Mozilla.