Splogs, where the money spills

So, I've read the now-popular Wired article:

Spam + Blogs = Trouble

and was shocked by one single number: "Between August and October of 2005, they made at least $71,136.89." Every time people discuss revenue from ads on the web I am taken aback. Maybe it's just that I'm not an ad-clicker, but where does this money come from? Why would you go to a website that only has gibberish and click on the ads on that page? I wouldn't, but it looks like $23+K worth of people do that every month only for these splogs from these BYU guys. Maybe not only on clicks, but also on impressions, but you have to have A LOT of trafic to make money out of ad impressions.

So, where is this money coming from? How can they maintain such a leak of excess money to bogus people? Only Google knows...