Wikipedia: DriftingQUOTE
Drifting competitions are judged based on line, angle, speed, and show factor. Line involves taking the correct line, which is usually announced beforehand by judges. The show factor is based on multiple things, such as the amount of smoke, how close the car is to the wall, and the crowd's reaction. Angle is the angle of a car in a drift, Speed is the speed entering a turn, the speed through a turn, and the speed exiting the turn; faster is better.
Team Drift Competition in Melbourne, Australia.
The judging takes place on just a small part of the circuit, a few linking corners that provide good viewing, and opportunities for drifting. The rest of the circuit is irrelevant, except as it pertains to setting up the car for the first judged corner. In the tandem passes, the lead driver often feints his or her entry to the first corner to upset the chase driver
So more show/entertainment than anything it seems