You've seen the Fast & Furious movies, maybe you've even caught some professional drift competitions on television or the web. But what does it mean when cars "drift?"
At it's most basic, a "drift" is movement of a car along some direction other than its steered trajectory, involving a slip angle at one or both axles.
While nothing about drifting is simple or easy to do--there's a great deal of both skill and art to drifting well--the concept itself is very simple: Drifting is when a car breaks traction with its rear wheels, spinning them continuously, typically while negotiating a curve or corner. Despite the appearance, a true drift is a controlled maneuver, not an uncontrolled slide.
There are many degrees of drifting, from the least-dramatic forms involving little more than some counter-steering and mild sliding, to the impressive displays of professionals, emitting volumes of smoke and noise as purpose-built drift cars slide through a corner at over 100 mph.
Some of you may know of this activity by other names--power sliding, "fishtailing", etc. While these activities are similar to drifting, the term is usually reserved for more skilful, intentional displays of the tail-out, counter-steered driving style, especially when such slides are chained together through a series of corners.
Because of the nature of drifting, the cars used to drift are almost exclusively rear-wheel drive. Front- and all-wheel-drive cars can perform similar maneuvers, but because the rear wheels can't spin at all in front-driver cars, and only at the same rate as the front wheels in all-wheel-drive cars, these other drive arrangements can't yield the same smoky result through the same means.
All-wheel-drive cars, especially rally cars, can execute four-wheel drifts, however, which use the same principles as rear-wheel-drive drifting, but with all four wheels spinning constantly, usually throwing up clouds of dirt and rocks in the process.
The primary series for professional drifting in the United States is Formula DRIFT.