Last weekend, I flew to and fro San Francisco and noticed something I'd never seen before. When you get off the plane and head for that room where your baggage takes a long, long time to tumble down a conveyor belt, you usually pass some limo drivers who are there to meet arriving passengers. They stand there holding up little signs on which they've chalked their passenger's name. But when I got to S.F., I saw five limo drivers and they were all holding up iPads, each of which had an arrivee's name displayed in a handsome font. And sure enough, there's even an app for that.