It's not about that. If the ads were only on their own domains, this could have gone undetected. The whole thing was discovered as a result of using those 'leg

It's not about that. If the ads were only on their own domains, this could have gone undetected. The whole thing was discovered as a result of using those 'legit' websites, and as far as I can tell from the article, using those was an essential part of the scam, i.e. without it, it might not work... but I'm just wondering why.