Is Big Data Creating Targeted Advertising?

Big data is being used to help predict and prevent catastrophic health events. We also can predict how effective a treatment is especially in behavior diseases such as type to diabedes, based on the information yourselpone knows about you. Are we 100 % accurate? It's hard to say when the results are an event not occurring negative observation. But if people to live better lives, then does it really matter? Don't get me wrong, it's creepy as b, but i'd like to think that we're really helping people.