It's called retargeting and they are using cookies to do it.
I'm just saying.. It happens more frequently which means it will be the next subject of legislation.. Spam (unsolicited) has been pretty well taken care of from my perspective.. I rarely see the madness I saw only 10 years ago. Someone pointed out earlier that we were bitching about the problem that we created, there is a lot of truth to that. It seems like every public communications infrastructure known to man has been a shouting/listening post to advertisers forever. Radio.. Then TV.. Then expanded tv.. Now the Internet and subsequently streaming tv.
Someone else pointed out the car that drove itself and freed you to watch ads. Demolition Man (don't hate..) actually depicted the same thing..
Cruising down the road in a society who is scared of everything, eating taco bell and listening to old commercials. And you get fined for saying naughty words..
Isn't that kind of what's happening?