Basically zero ads are just static images with a link, they're dynamically loaded by JS when you open the page. The JS collects as much tracking data about you as it can, sends that off to the ad network servers which run a live auction to determine who will pay the most to show an ad to you right now, then returns that ad for the JS to display.

AdNauseam not loading the response to the "click" request makes it trivially easy to flag as fraudulent, because a real click would load and run the response.