I’m looking into training courses for Exchange 2010, and to add a course to “My Learning,” which I guess is the equivalent of a shopping cart, I had to sign in with my Live.com ID. I have a Live.com ID because you need one to see your MS licenses and download ISOs, etc. It’s not as seamless as Google’s ID but it seems to work ok most of the time. But here’s an instance where it sucks:
I’m already logged in, why do I need to input all my info again? Including my email address, which was required to login?
Evan Hoffman's Blog 