Microsoft Passport has been around for a while. This article describes the Risks of the Passport Single Signon Protocol extensively. Contrary to my personal preferences and beliefs; I myself have been using passport for quite a while just because of the large list of participating sites that I frequent.
However the frequent presentation of the following screenshot is compelling me to believe that someone needs to get their act together and also give other alternatives a shot...

This is a very good example of how a single point of failure can cause serious impact on business processes.
