Yes, yes they absolutely do, although not quite at the levels and extent you might think. I worked with an ad network DSP, who's entire business was figuring out what crap to put in front of what users.

All I'll say is that they used pretty low down ways to get to people, one example that sticks out was the amount of targeting that went on late Friday, late Saturday night in APAC when folks would stumble home drunk and go online.

Everything and the kitchen sink was thrown at these people, and it often resulted in multi thousand dollar sales, including a few automobiles!