How Target can deduce pregnancies, create new habits, and know what you want before you do | The Verge

This is one of those things that we all know happens but no one wants to hear. A disterbing example from the article: 

In one case, a teenage girl started receiving coupons for cribs and maternity clothes in the mail. The father, irate, came to Target to complain — only to find out a few weeks later that his daughter was, in fact, pregnant.