Finally!
Want to serve up ads for yarn when I'm browsing Ravelry? Cool.
Want to try to sell me your series of graded readers for language learners when I'm using the Duolingo app? No problem.
Want to set up a giant dragnet surveillance operation and then cross-link all the bits of information you collect about me into a giant profile that you can feed into a horrendous rat's nest of math you barely understand, but can plausibly deny you weren't aware was subtly profiling me based on indicators of my race or sex, in order to decide whether or not you want to try to track me down and sell me on some fancy mail-order-only brand of underwear while I'm at work? Let's slow down here.