You may not know it, but you probably have an OpenID. If you have a Yahoo account, you have an OpenID. If you have a Windows Live account, you will soon have an OpenID. And today, if you have a Google e-mail account, you can also start using your Gmail address as an OpenID.
By joining the OpenID movement, Google completes the trifecta and adds all of its Gmail users to the hundreds of millions of Yahoo and Windows Live accounts that can also be used as a single login for any Website that accepts OpenID. While Google is more than happy to become an issuer of OpenIDs, what is not so clear is whether it will accept other OpenIDs for people who want to sign up for Google services.
Google appears to be an OpenID “provider,” not a “relying party.” In other words, you cannot sign into Google with your Yahoo account. But this still helps the OpenID movement as a whole because it gives smaller sites more incentive to join as “relying parties.” Among the first sites to accept Gmail accounts for sign in are Zoho and Plaxo.
AOL and MySpace are expected to jump aboard as OpenID providers as well. The only big holdout appears to be Facebook, which has its own competing Facebook Connect program. But even Facebook might eventually join the OpenID fold. (Its partners seem slightly less than enthusiastic about deploying Facebook Connect).