Just a few days after Uber got the official go-ahead to operate under a New York City pilot program for taxi-hailing apps, the UberTAXI service has gone live. There are a few limitations at present, however. The app doesn't support automatic payments, so you'll have to remember to pay your driver the regular way, and Uber warns that cabs may be in short supply to begin with. You'll also have to explicitly request a taxi rather than a black car, and you won't be able to use UberTAXI to travel from airports because of regulatory pitfalls. Still, the service's NYC resurrection six months after it shut down is a major milestone in the long-running battle for taxi-hailing apps to gain official acceptance.