Most of the fear about this new development - which has lots of precedent as you point out - comes from the media outlets for whom this is another nail in their coffin. Maybe you're agreeing with me on this (it's not entirely clear to me), but I think Google becoming the highway patrol means they've crossed a line not yet crossed before, one that I think will give them enough power that they probably can't resist using it on their ad competitors. I worry that the reverberations will be felt in many more places than just at media companies that should've been dead already - if your 30% suddenly became 18%, I think you'd notice. I'd actually love to know what ad agencies think of this, especially since you posted a while ago about how they hate how online (video) ads are organized these days.