[randomdude402]

The advertisers don't obtain the data. The articles that discuss this are always careful to use phrases like they "use" the data.

They set up an ad campaign in Facebook or Google or another similar network, and they have to decide who to "target."

Google and Facebook, and other networks to a much lesser extent and perhaps through other apps that people wouldn't expect to be related, have tremendous data troves about people.

This includes phone location data and history, and data from partners about things like what types of purchases a person makes on their credit cards, whether they are a homeowner and their home value, income... things like that.

All the advertisers actually get is the ability to say something along the lines of "This ad should show to people who were at or near X location and make less than X amount of money."

They don't "get" the data or have it "sold" to them. They are able to "use" the data in a very indirect way.