Note that he was not always clicking on the links, to maintain a reasonable low clickthrough rate for the ads.
You run a video site or a search engine that serves CPM ads. If you can buy PPC cheap enough, you can arbitrage and make money.
PPC from Google is expensive, but there are companies that sell cheap clicks. Some publishers on these ad networks run porn sites with hidden iframes that generate the clickthrough.
However, iframes generate a http referer, and this gives away the rather dubious traffic sources. The series of redirected clicks are used to subvert click fraud analysis.