Stop me if you've heard this before...

You're at a store checkout counter and the person ringing up the sale asks for your zip code. I can't count the number of times this has happened to me. And without thinking, most of us give them the number.

If you have done this, you may want to stop. It seems that with that little piece of information, you could be letting a company know a whole lot more about you than you think.

Get the full scoop here.