This is an enormous win for OpenID, but it is also a huge risk if anything goes wrong with such a high-profile project. Obviously, it will all depend on the implementation, and if all goes well it will give OpenID the push it needs to increase the number of consumers as opposed to providers, which is a ratio that is sorely lopsided at the moment.
I’m a little sad to see that my preferred OpenID provider, myOpenID from JanRain, Inc., was not included in the approved list of providers for the pilot program. Hopefully, that will be rectified soon, although even if it does not, one of the great things about the OpenID protocol is that delegation means that I can change providers on a whim. :-)