Why does Single Sign In (Single Sign On) suck? Because its centralized and one broken link kills all! I have been trying to log in to OfficeLive for the past few minutes to work on my website, but because it uses Passport to log in, Passport, OfficeLive and the interacting APIs between them must all be functioning. In this case, OfficeLive and Passport both seem to be working, but the OfficeLive link to Passport is preventing me from being able to manage my new websites through OfficeLive.
Single Sign In services are only a good idea when they work, but all people implementing them should consider having a backup plan.