All major airports have at least one, but it's only certain (European) countries that seem to use them regularly. Germany, Spain and Portugal spring to mind. Here in the UK it is only sent out, manned by one of the operations staff drivers, if it is apparent that a visiting pilot doesn't seem to understand the radio taxiing instructions. Don't laugh, this happens!

At Faro in Portugal, years ago when I was a kid, I remember the arriving charter flights were led round by little Follow-me Minivans which showed the pilots they were going to turn left or right on the taxiways by using their direction indicators!