According to Wikipedia:
Powershifting (a.k.a. flat shifting, full throttle shift, or clutchless shift) is a method of shifting used with manual transmissions to reduce the time where the driving wheels are not powered.
Unlike a normal gearchange in a manual transmission,
a powershift does not utilize the clutch at all. Instead, the gear lever is "ripped" from gear to gear. If tried with a road car, this can cause catastrophic damage if not selected in the right RPM range, especially if the gearbox doesn't have synchromesh.
OMG

WHAT ON EARTH ARE VW DRIVER MAG UPTO? Do they test all their cars like this?! Thats not a meaningful 0-60 time at all.... I'm really suprised that VW let them get away with it. Changing gears on a manual WITHOUT using the clutch - thats madness. I'm sure they don't do that with every test car so why the manual GTI? Maybe someone over there just wants to show that manual is faster than DSG.... it confused the hell out of me when I read the 0-60 time for the manual on a standard GTI in VW Driver mag as being 6 seconds - versus 6.2 for the DSG... but that explains it all.