To all the people saying this isn't a problem: it really is. Even if advertisers bake a fraud premium into their buys, blindly letting money flow to bad actors creates an incentive to be a bad actor, and bad actors in this space do bad things that hurt everyone: waste massive amounts of bandwidth, spam the web and app ecosystems with worthless content, and worst of all exploit users to build and run botnets.

We've spent a lot of effort over the last few years fighting this stuff, and we're really happy to see the industry as a whole starting to agree that it's a problem. If you'd like to help make the web better by working to remove these incentives, we're hiring engineers; contact info in my profile.