but isn't views also what you want when you're showing ads? I mean clicking on the ad would be preferable I guess, but I'm not sure how tightly correlated that

but isn't views also what you want when you're showing ads? I mean clicking on the ad would be preferable I guess, but I'm not sure how tightly correlated that is to users clicking on user generated content. I can see Facebook wanting to sell views rather than clicks to their customers.