Google is all about an open Internet, even with the threat of several anti-trust investigations looming, and it is a strong backer of open web technologies.
What this means is that millions of users would be able to log in to the large number of sites supporting OpenID, still not large enough though, with their credentials from work or school. The feature isn't officially launched yet but it was made public by mistake by Eric Sachs, Google security product manager, on an OpenID mailing list and picked up by the Read Write Web blog.
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