Well done to him for making 8k out of it already.
No idea why people are bothering to buy space though... Sure it's going to do the viral thing for a while, and while there's not much on it so to start with a few people will get clicks... Of course the more people that get on there the less visible links will be and the less likely to get clicks... Also none of the clicks will be targetted in any way with such a small space.
Also the more people that buy links on there the more it may become seen by search engines as a link-farm so once the viral effect wears off it will be dead.
But much as I think anyone buying space on there must have money to burn, as it is far from a viable advertising medium, I still have to big him up for making money from this shit.
Some nice creativity from the advertisers in the small space available I guess... Particularly like the idea of the bottom right corner, possibly making people think their link leads to another page within the site and getting a click. Albeit an unqualified and useless click.