Aquaplaning is a slide created by the car skimming over water, it is caused in fast straights, normally when passing over watersplashes. It is also caused during sharp cornering, where the tire also has the job of turning the car.
Aquaplaning is usually resulted by fast driving with tires that are not in good shape. The feel is normally that the engine revs increase, while speed seem to decrease. Normally, the front tires skim, and the rear stay generally intact. As seen in the video, the steering wheel is rendered useless and will only destabilize the car (resulting in a spin in the video). There are several options of solution:
1. Ease off of the throttle, to allow speed to be scrubbed-off, and grip to be restored. Typically, the driver should not ease-off of the throttle comepletly, but release it gently and keep it just covered with the foot. If this does not seem to help, carefully ease-off of the gas (be especially carefull in RWD cars, AWD cars are usually much safer in this case). If you need to brake, brake lightly and release and than reapply if nessecary (do not pump!).
2. Reapply power: Putting in more power (typically in a FWD or some AWD cars) in a balanced manner can help the tires reach through the water. It is recommended to ease-off the gas, and -- if that does not help -- reapply it very lightly. Left foot braking helps in this whole procedure, but takes a lot of sensitivity, so using the right foot might be more advantagous.
4. De-clutch: This works very well in manual cars. It reduces engine drag, enabling the wheels to re-grip the surface.
5. Emergency braking: If you need to brake, either just touch the brakes carefully, or stomp it. If the cars attempts to spin, you are probably not going to make it (E.G. the video) and should just brake hard and fast ("Both feet in"). This is not likely to stop you spinning (like in normal oversteer), but can make you spin in a straight line, unlike the driver in the video who countersteered (for no good) and spun twice and across the track.