The OpenID logo is a stylized letter O, logo of a company, the OpenID logo is the OpenID OpenID OpenID logo.
The OpenID logo is a stylized letter "O". 

The OpenID logo is an open authentication mechanism. 

OpenID uses an identifier-for-later authentication scheme: a user presents an identifier from an OpenID service provider when requested to access a service, and then accesses the service in a trusted session without further need for the user to intervene.

The OpenID logo is often confused with OAuth.