From today you can use your e-mail account from Google as OpenID provider, but nothing to access its services with the exception of the comments on Blogger. This is the same position on OpenID taken by the blog hosting service in the house – Blogger – and other providers like Yahoo!, Launchpad and Windows Live (Microsoft) starting next year. It does not appear that none of them is willing to lose control over the data, and once again, are not allowed to use OpenID to identify its services.
The only difference with the rest, is that for any other page it allows you to identify yourself as a user using a Google account, it must use an API-based OpenID 2.0 with limited access and that is not yet public. . As a user, using e-mail addresses through the API it is easy to remember your ID, but as a developer it does not allow you to take advantage of the current implementations of OpenID protocol.
The first site that is using this form of identification in its entire range of productivity tools and collaboration, among which are those that compete directly with Google Docs, Zoho. To use it, just click the link that appears below the boxes of identification and which are also available on Yahoo!