It's not a question of how much money they make, but how they make it. An advertisement should be a one-way channel from the publisher to the audience. If information is flowing in the other direction (particularly if without the audience member's express permission) then it's become something more than an advertisement and that's a good place to draw the line.
Having more data about you allows them to pick out 'better' ads and make more money. Wether this money goes to ad networks or content creators depends on how much leverage one has over the other.