We have all visited websites and seen advertising that eerily matches searches we have done or pages we have visited. Sometimes it’s as if our computers actually know what you have purchased or are interested in purchasing, without you telling anyone. With the recent disclosures of Facebook’s data issues, people are more interested than ever to understand the ins and outs of ad targeting. So how does Facebook and other sites learn so much about us? One way is through our purchase behavior. You walk into CVS and buy Kleenex and Afrin. The next day you start seeing ads for [...]