Originally Posted by 2MuchMark

It probably doesn't have enough surface area to absorb that much moisture. Moisture will stick to your windows before sticking to this, and stay there.

Do this instead: When you start your car, turn on your defogger to max AND open your windows a little. This will help dry out the are and push some moisture out of your car at the same time. Doing both at the same time defogs your windows faster than just doing one or the other.