Edit: also who you vote for, what laws are passed, who goes to prison, who lives and who dies. But no they don't _directly_ give you cancer.

Do people know the risks of being profiled by ad companies? I am not sure most people can even begin to understand the associated risk. The few attempts to show people what companies know about you were shut down pretty hard.

So did the ads that told people to smoke. They were banned precisely because they were driving behavior that causes harm.