According to a new survey from Consumer Reports, an estimated 13 million Americans don't make use of Facebook's built-in privacy controls. The survey looked at 2,002 adults with a home internet connection and found that a large number publicly shared some sort of potentially private personal details on the network last year. A projected 39.3 million named a family member in their profile, 20.4 million listed their birth date, while millions more liked a Facebook page related to a religious group or sexual orientation.

For many of us these are minor issues, and in some cases they're the result of bad decisions as opposed to Facebook's privacy settings — such as the 2.6 million people who boasted about drinking alcohol. But Consumer Reports does point out a few instances when seemingly harmless information could be used against you. For instance, posting about when you're leaving the house could alert criminals that your home is empty (something 4.8 million people did last year), while discussing health conditions or liking related pages could provide useful information to insurance companies (which 4.7 million did).

Whether or not you believe these dangers are real, the potential is certainly there, and the best defense is to simply understand the privacy tools so you know exactly what information goes public. You might not get robbed, but better safe than sorry.