According to Wired, Yahoo’s adoption of OpenID is a huge victory for the OpenID foundation.
Until now, despite support from larger sites like AOL and Plaxo, OpenID has remained largely a tool of the geek-elite, but Yahoo’s announcement is set to change that since it provides even those Yahoo users who’ve never heard of OpenID a simple way to use it. And that in turn gives startup sites an even greater incentive to support OpenID logins.
Right now there are roughly 120 million OpenID accounts. Add Yahoo’s 248 million users worldwide, and OpenID is set to triple in size.