It adjusts brakes and engine speed to each individual wheel to keep you in your intended direction.
Correct. Here are good videos explaining GM's Stabilitrak:
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Basically very fast computer processors and such monitoring forces, slipping, etc. occurring while driving and apply single or multiple wheel braking, regulate power application, etc. to keep the car in line and steady. Different from the also included traction control which the main purpose of is to control power delivery at the drive wheels alone via braking or power reduction when slipping is noticed, versus controlling the stability of the entire car.