Picture this: You are demonstrating a sample. You have done the same thing earlier. It always worked. And then it failed with a cryptic exception you never saw before.
Unhandled Exception: System.ServiceModel.AddressAccessDeniedException: HTTP could not register URL http://+:2222/. Your process does not have access rights to this namespace
This is exactly what hit me while demonstrating a WCF example for the first time on Windows Vista. Of course it was only later I realized it is because of windows Vista. In fact this is what anybody running vista is bound to come across. So I felt duty bound to document it.