Well maybe apps like Facebook (=Instagram), Apple Weather, Gmaps will "only" use your data internally, but they also make most of their money from ads. So yes, all our data is always used to target ads, political campaigns and "viral" marketing campaigns at us. Where is the surprise in that? If you asked 2007 software engineering student me, I would've told you back then. That was the point in time where this work started. Nowadays everybody is doing it themselves or selling the data one way or another.

Don't you know that also this very post will be grabbed by multiple people and companies and analysed to death by their algorithms to maybe squeeze out another bit of information that they then try to link to me as a person in some way?

So if you sit there wondering "does the app X that I'm using does that?" then the answer is yes, because everybody is doing it.