Microsoft Passport
Microsoft Passport is a "universal-login" service provided by
Microsoft that allows users to log in to many
websites using one account. Many of these websites include MS services such as
Hotmail,
MSN Messenger or
MSN subscriptions, but there are also many outside companies affiliated with Microsoft that use it, such as
Radio Shack.
Users of Hotmail or MSN automatically have a Microsoft Passport that corresponds to their accounts there.
The Passport is in a work-as-they-go stage. Bugs, such as the one on May 8th, are still being uncovered.