In 2008 I worked for an ad network and we dealt with a massive amount of fraudulent traffic. We did our best to shield our advertisers from the obviously bogus

In 2008 I worked for an ad network and we dealt with a massive amount of fraudulent traffic. We did our best to shield our advertisers from the obviously bogus traffic, as it absolutely killed traffic quality and inflated CPAs. However some advertisers, notably one large video game/entertainment website, wanted to purchase as much traffic as possible, and they were overjoyed to get the bot traffic (which went for a CPC of about $0.001). They were buying $10-20k per day from us of fraudulent traffic. Turns out they were relying on the audience engagement platforms (alexa, hitwise, quantcast, comscore, etc) to track their audience size and those platforms incorrectly counted our bot traffic as legitimate. As the majority of their advertisers were brand marketing (e.g. Nintendo paying for a full-site background spread for the latest Zelda) and there was no direct way to measure success, advertisers would be swayed by the third-party audience profiles and agree it was good idea to spend massive amounts of money on ad campaigns there.