Comment by picodguyo

I observed the same with Google's "Smart" display ads. I ran a campaign for a couple of weeks and watched all of the traffic with HotJar. The first fishy thing was 99.9% of the traffic came from foreign countries despite the target being US/Canada. When I saw the targeting wasn't effective, I even set up specific geographic exclusions for every country != US/Canada and still the traffic was from mostly underdeveloped countries. Then there was the behavior of the "users" when they visited the site. A large percentage of them went straight to the search box (which literally no humans do on the site) and typed in something topical but completely unrelated to the site's topic, e.g. "covid". Another large percentage just scrolled up and down randomly. It was interesting to see the size and relative sophistication of the fraud going on but not exactly $500 well spent.