Adtech in general is kind of difficult to grok at first. It's dense with jargon and is largely driven by partnerships and resale. To a newcomer the industry can

Adtech in general is kind of difficult to grok at first. It's dense with jargon and is largely driven by partnerships and resale. To a newcomer the industry can be very opaque. It's likely they weren't working on the actual ad injection itself, but rather the backend systems that select and count the ads. From that perspective it's just a matter of handling X requests per second, without it necessarily being clear where the traffic comes from. When I worked at Adzerk, we'd be approached occasionally by companies doing this kind of garbage. They were always very good at disguising their actual traffic sources. Our sales team had to be very adept at asking the right questions to eliminate the shitty partners quickly.