Update 2: I didn't know this, but it turns out Apple Safari is *also* spying on what ads you view and click on, and sending that info (with some anonymization) directly to advertisers via a backchannel?
It's worse documented than the Firefox/Chrome versions, and like Firefox (unlike Chrome) there is no clickthrough consent. I don't expect better of Apple, but this *grates* given they're running big "A browser that's actually private." billboard ads in my neighborhood.
@mcc Well it is privately spying on you. The others do it publicly. Or something like that. I would like to have a law that makes tracking illegal.