Don't know if they actually make money but their costs are minimal. Those are the bottom of the barrel ads that ad networks serve up when nobody else actually wants to pay for the impression - either because a site is crap or because there's not enough info to target anything more profitable at you.

Also related to the ads, does anyone have some marketing distillation of why they always use the words "weird trick"? Weird trick for weight loss, weird trick for language learning, etc.