Traction control is a nice, new feature that uses the anti-lock brake sensors at the wheels to determine if a wheel is slipping. If it detects that one wheel is going faster than the others, it applies the brakes to that wheel until it regains traction. That helps keep the car from slipping around in the rain and snow.

I say leave it on unless you need to bust thru a snow bank or get stuck and need to rock the car back and forth.

 

It's the, "I wanna do a burnout" button.

 

It's a traction control/Vehicle Stability Control button, it helps your car keep traction, pretty simple. If you push it once, it turns off traction control. It's not often you'll want to turn off traction control, but it'll let you spin the tires to do a burnout or help get unstuck if you get stuck in snow etc. One push still leaves VSC on, so once you start going side ways it will step in. It tries to stop you from killing yourself.
If you press and hold it for around 5 seconds while stopped, both traction control and VSC are disabled. At this point the car will let you do any shenanigans you want. From full on burnouts, to drifts and donuts - yes believe it or not the LS can do some sweet burnouts and donuts. The car will not try to stop you from killing yourself. On cars with advanced systems such as Radar Cruise Control, Pre-Collision, Lane Keep Assist, etc, all those systems are disabled as well. So if you happen to screw up... You're toast.

 

Just like the good 'ol days!