Reading blackhat SEO forums is enlightening. A lot of these guys operate large setups where they convert a few dollars of AdWords clicks at a time into a few mo

Reading blackhat SEO forums is enlightening. A lot of these guys operate large setups where they convert a few dollars of AdWords clicks at a time into a few more dollars in AdSense revenue by funneling the traffic around in various ways. Multiply by a couple hundred or a couple thousand servers, and you're talking about some serious cash.