if you only press the button momentarily, it only turns off the traction control (says 'traction control off" in the driver info center)...ie, straight line wheel spin control...like doing a straight line burnout. If you start to swerve/risk rolling over/do donuts it will still correct, thats the stability control (stabilitrak).
to turn off the stabilitrak completely so you can do burnouts and donuts/slide sideways and stuff, you have to press and hold the button for 5 seconds and it will say "stabilitrak off" in the driver info center.
make sense?
ben