Robert Spier had a great explanation of the difference between authentication and authorization in his single-sigon talk.
Think of your conference badge. The name on it that says who you are is authentication. The color of the badge that says what you can get into is authorization. Nice.
After the talk, I gave him a 32-oz. diet Coke that I had to get from 3 blocks away, since the hotel was all-Pepsi.
