Keith Chan found what looks like it might be an experimental form of Google AdSense.
As the screenshot by Keith shows, there are two blue arrow icons at the bottom left of the text ad unit.
Clicking the down arrow scrolls into view a couple of new ads. Keith also made a video at his GSpy blog showing this in action.
I suppose Google is still polling usage statistics at this time to see if this kind of ads may work.
If I had to take a guess I'd say there won't be a large amount of people pushing that scroll button; sometimes an AdSense ad accidentally catches your attention because it's relevant, but the incentive to go look f ...
