Basically what is does is when you come to a stop at, say, a traffic light, the car turns itself off. When you press the clutch (or I guess the gas pedal on DCT), the car automatically turns itself back on so you can keep driving. It's supposedly a way to be economical and save gas. Hope that helps!
2011.5 SG E92 ///M3 6MT | CF kidney grills | IND SG painted side grills w/ tinted lenses | Painted bumper reflectors | TMS 90mm stud kit | Rear fog light mod | Active Autowerke exhaust |