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

This is one of those things that we all know happens but no one wants to hear. A disturbing 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.