With a driver, backspin is one of the keys to distance. Without getting too detailed, the spin starts about at about 2700/3000 rpm backspin. It slows as it goes, and that is affected mostly by time aloft. Time aloft of 7.0 - 7.3 seconds is awesome.
Some combination of rpm/speed produces optimal lift. The right rpm/forward speed combo at the high point of the drive's arc causes the ball to kind of hang there a short while, and that gives you an extra 20 or 30 yards if things are right. If the spin rate hits optimal too early the ball balloons, too late and you miss the advantage.
Launch angle, backspin, speed .. all keys to the distance, and finding the right head/shaft/ball combo for your swing is why they have so many of last-years' drivers for sale cheap on e-bay.