These 'cookies' aren't tasty; you're left hungry for privacy.

[Commentary] What if the next time you visited your local mall, a gaggle of detectives quietly followed you around taking notes on every store you visited, every item you bought, every movie you saw. Let's say they followed you to a bookstore, where you looked at books on treating cancer and depression. Then they started whispering that you might have cancer or psychological problems. At that point, you'd surely tell them to hand over their notebooks and get lost. Well, companies of many types are routinely doing just that — keeping tabs on your interests, purchases, likes and dislikes and making major assumptions about you — every time you surf the Internet.