Microsoft is taking its first major step towards OpenID adoption by becoming an OID provider. Once enabled, users will be able to login to any OpenID enabled site with their existing Windows Live IDs. The first iteration is provider only—it will not be possible to use other OpenID providers with Windows Live services, unfortunately.

While we're generally pretty down on "provider only" OpenID implementations, Windows Live has enough members to make this announcement pretty exciting for OpenID proponents. Yahoo, AOL, and Microsoft users can now login to any OpenID enabled site using their existing user accounts. Google users can as well, though it's through an unsupported AppEngine implementation.

Although OpenID is becoming a viable option for independent sites, particularly after this announcement, there's still a great deal of friction preventing serious uptake. Major Internet hubs that offer OpenID are generally providers only, so a Windows Live user is still going to need a Yahoo account to use any Yahoo service. As long as this is the case, the utility of OpenID will be constrained.

Even assuming 100 percent OpenID coverage, there's still a massive UI problem to overcome. In many cases, users don't have any idea what OpenID is, simply don't understand how to use it, or can't wrap their head around the concept of "using an account from another service to login." With this announcement, millions more people will have an OpenID enabled login account somewhere, but it's still quite a long road to real adoption.

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