These kinds of pieces are sort of accurate. I have run a lot of ad campaigns on Google and Facebook (I don't do this kind of work today), and if this kind of th

These kinds of pieces are sort of accurate. I have run a lot of ad campaigns on Google and Facebook (I don't do this kind of work today), and if this kind of thing comes up in conversation, I like to say that anybody can set up an ads account with Facebook or Google and see how it actually works. Yes, you can create an ad and set it up to target people live within a certain area or have visited a certain area (and/or a number of quite creepier feeling criteria), but that's it. They are not "selling your data" to advertisers. As an advertiser, all you get is some statistics about who your ads got served to, and they are pretty shitty and vague. "You said you were willing to pay $10.00 USD per click for people who have been within (LAT,LNG of XYZ hospital) within the last 30 days. We declare that 150 of the 200 ad clickers have indeed visited that location. That will be $1,500 USD plus some lesser amount for the other clickers that we somehow served your ad to. Let's call it $1700, we'll take it out of the prepaid account you had to set up before we even ran the campaign. Thanks for advertising with us, and if you don't like it, good luck finding another ad network with anything approaching the same exposure."