The current state of affairs led me to believe that there's no big difference between data brokers and intelligence agencies from a citizen/sw_user perspective: they use shading techniques to extort and intercept data about people, from people, giving them to other people, for unclear and/or deplorable aims.

Terrorism and marketing are two reasons looking for a question, the reality is that who's doing this wants the power that comes with knowledge, and there's absolutely no difference between an intelligence agency and a data broker in this.