Increasingly, digital ad viewers aren’t human. A study done last year in conjunction with the Association of National Advertisers embedded billions of digital ads with code designed to determine who or what was seeing them. Eleven percent of display ads and almost a quarter of video ads were “viewed” by software, not people. According to the ANA study, which was conducted by the security firm White Ops and is titled The Bot Baseline: Fraud In Digital Advertising, fake traffic will cost advertisers $6.3 billion this year. ... Fake traffic has become a commodity. There’s malware for generating it and brokers who sell it. Some companies pay for it intentionally, some accidentally, and some prefer not to ask where their traffic comes from. It’s given rise to an industry of countermeasures, which inspire counter-countermeasures. ... All a budding media mogul—whether a website operator or a traffic supplier—has to do to make money is arbitrage: Buy low, sell high. The art is making the fake traffic look real, often by sprucing up websites with just enough content to make them appear authentic. Programmatic ad-buying systems don’t necessarily differentiate between real users and bots, or between websites with fresh, original work, and Potemkin sites camouflaged with stock photos and cut-and-paste articles.