We can remember a time when all you did during a cab ride was watch the city zoom by outside your window and quietly contemplate your mortality. Now, a few years after the introduction of Taxi TV, Jack Dorsey of Twitter fame wants to embed tablets and his Square mobile-payment technology into the backseat divider, allowing you to swipe your credit card at any time during the trip, as well as occupy yourself with games and a million other things. We guess it's inevitable — that's the world we live in now. People don't make time to just sit anymore.