And a profit-maximizing one at that. They've got plenty of money but they need as much as possible, no different from a Zuck enterprise in that regard.

And is their rake on that correlated with site views? I'd guess not so linearly like it is with ad impressions. It is a different business model.

Pedantic without a point. A first-party ad for support of the platform is entirely a different category than running ads for other services, served from third-party ad companies.