I started a news aggregator that at the peak was ranked in the top ten Alexa sites in a country (was doing 100M page views / month). Alexa was the standard that

I started a news aggregator that at the peak was ranked in the top ten Alexa sites in a country (was doing 100M page views / month). Alexa was the standard that people would use to judge how successful a site was.... Until people figured out how to massively game it. For a pretty small sum, you could approach illegal download or porn sites to embed an iframe of your site or do a pop-under ad, and instantly be in the top 10. People aren't actually visiting your site, you're just getting "shadow traffic". Then you'd go tell advertisers "look, we are one of the biggest sites in the country". We didn't play that game but our competitors did and it was really frustrating. Anyway, the point is their rankings weren't very reliable (this was 8+ years ago, maybe they've gotten better at detecting traffic fraud).