If you the same thing again, but with an expensive 1080p video camcorder, it has no blur at all.
So there must be some sort of sensor property that causes this effect, i just dont know what its called.
afaik, its called sensor size and sensitivity issue. the solution... money. and of course size, ie, dont expect small sensor to achieve shoulder mount (or even the palm sized) camcorder performance.
edit1: sensor size means, the single sensor size (or pitch), not the whole array in the rectangle. and of course... single sensor size x pixels count = add up to the rectangle (people simply say as "sensor") size.
edit2: i suspect the motion blur on 1080 webcam you are talking about is due to software. ie, the sensor is capable of capturing at said resolution and speed, but the hardware is not capable of transferring all the details (individual frames) at such speed, so the fabulous software is made to combine several frames as one to save bandwitdh. is what you saw in your monitor as blur (combination of many movements/frames in one single frame).