based on a wmw discussion, here's how it works:
He's selling ad space like his million pixel shit-brigade. Visitors register, and click his ads, and get one entry for each ad they click, with a limite of 10 each day. 30 days after all the ads are sold, one ad is picked at random, and then a winner is chosen at random from the people that clicked on that ad.
I can't really see how this benefits advertisers, since they'll just get lots of completely untargeted traffic who won't even probably look where they clicked, but it'll probably sell out because hey, it's Alex Tew wonder-kid, and we'll all kick ourselves for not having thought of it first.