I decided that although it would probably be cool if individuals could buy a single pixel each, in practise, it wouldn't so effective. The reason I believe this is because you can't display anything meaningful in one pixel - nor click it easily - so visually, it would be pointless. With thousands of random tiny coloured dots all over the place, the homepage would look gastly.

I also thought that the site would appeal more to people with businesses/websites to advertise than it would to individuals, or to put it more accurately, businesses would pay more to have a meaningful graphic on the homepage. Hence the minimum purchase is $10 - for 100 pixels.

However! If you really want to own a single pixel, there is always the option of clubbing together with your friends/family/colleauges and buying a 100 pixels block.