Quote Originally Posted by yudalicious
since in today's world pads do not outgas anymore, the only real function drilled holes serve is to reduce unsprung weight... the slots effectively "shaves" a layer of pad material off, keeping the pad fresh, perhaps that's what you meant by increasing drag coefficient (or rather, friction).
for 2) i would like to add that people who are using this "train of thought" are probably using bigger brakes and the longer lever arm by the bigger calipers farther away from the center of the rotor to generate more brake torque (which is what stops the car) to compensate for the comparatively less aggressive (lower friction force) brake pads. Again it is important to use quality rotors.

edit: i am using hawk HPS (hardly an aggressive compound) and brembo blanks, and they have served me well for a street car, dusts quite a bit though, tht's my biggest complain with them. I am going to run hP+ next time.
explaining it in person and explaining it in text is sometimes difficult, you got what i meant