It depends what kind of traction control (TCS) system the car is
equipped to start with.
If it's a passive system like what a friend of mine did in a
Volkswagen Passat 2.8 V6 at the 99 turns, then it's just cutting
off excess torque from the engine and thus reducing
wheelspin.
However, the brakes are not activated like on an active traction
control (TCS) system, also known as stability control (VSC)
Now, certain cars comes with stability control(VSC), and that cuts
off excess engine torque, as well as applying individual brakes on
the spinning wheel with excessive torque, without the driver
tapping on the foot brake !
The active system works very quickly that you almost cannot detect
it's presence , except with some slight intruding mechnical noises
and the flickering of the TCS light on the dashboard to tell the
driver the system is actively cutting in to reduce excessive power
!
I prefer cars with active traction control(VSC) as it makes almost
any average driver capable of driving and flooring the throttle,
and taking a corner without fear as the electronics are taking over
and making you look like Michael Schumcaher when in fact you are
just an ordinary driver !
HOWEVER, do take note that we should not tamper with the law of
physics and no matter how clever modern TCS or electronics are,
accidents will happen if we do not practice safe and considerate
driving !
The TCS or VSC is a device to aid drivers in adverse condition
especially on slippery roads like wet weathers etc.
Hence, enjoy your driving pleasure, but maintain safety ! 
