As a lifelong Californian "What's a cab?"
I saw them on a game show on TV. You get in this car and tell the driver where you want to go. He will drive you there and ask question on the way. If you answer the question right he gives you money, but if you get three of them wrong he will kick you out of the car. And you walk.
I saw this show about "taxis" on HBO. Apparently you get in this car and tell the driver every perverted thing you did or are doing that night, and over the course of your life for that matter, and you get filmed and they show it on TV. I think they even drive you someplace.