Google, Yahoo!, and MySpace have launched support for the OpenID OAuth Hybrid Protocol, which combines OpenID authentication (sign in) with OAuth authorization (access control) into a single interface. Websites that accept OpenID can now let the hundreds of millions of users who already have either a MySpace, Google, or Yahoo! account sign in and enable two-way data sharing of their profile, contacts, and activities, without having to register a new site-specific account or to share their password.

Plaxo is one of the earliest adopters of OpenID, allowing their users to sign into Plaxo using an OpenID enabled account with just a couple mouse clicks. Instead of requiring first-time Plaxo users to manually verify their email address by sending a verification email, Plaxo uses OpenID Attribute Exchange to verify Yahoo! and GMail email addresses without forcing users to wait at their mailbox for the verification email to arrive. Building on their successful experience with OpenID, Plaxo is experimenting with the Hybrid Protocol: A portion of new users who sign up