The value proof in the backend that convinces advertisers to throw more many at this? Mostly rule of thumb heuristics with a fair amount of overselling. So no,

The value proof in the backend that convinces advertisers to throw more many at this? Mostly rule of thumb heuristics with a fair amount of overselling. So no, in most cases the telemetry just doesn't prove much. I've seen the thesis that all this advertising revenue - even if poorly spent - subvents large portions of exciting research in deep learning etc. at the likes of Google and Facebook. So all that talent wouldn't entirely be lost to advertising.