This is kinda old news, but it's making the rounds again on Facebook and other social media.   If you take pictures and post them to Facebook on your smartphone, you may be giving away the location of where you live or where you took the photo.   This is especially frightening to people with children. 

This video explains it all, and at the end shows you how you can prevent this.   I checked my phone and it was turned off, however some co-workers checked and they had this feature enabled.  Scary stuff.