Interesting. I'm wondering what the benefit of infinite scrolling would be for the site owner. Wouldn't an article site like this want the user to click as many links within the site as possible to re-generate ads?
I don't think ALL of the ads are generated when you load the original page. The ads corresponding to the second article are loaded when the second article loads.
I am guessing the same mechanism that allows them to change the url on scroll, would be used to change/reload the ads as well.