> * And it has to come from the ad networks, because the infrastructure to make this work is already there*

That really chaps my ass. These are the people keep shitting in the well, then installed a pipe to inject feces directly into the well and the groundwater - and you're telling us that the only way to deliver disinfectant and filtration systems is through that pipe, and we might as well keep using their system?

> The real trouble being the more people who use that kind of thing, the more the value of adverts goes down...

That does become a problem if Google is the only game in town, and you're inexplicably banned from their platform, which does tend to happen.