There was a power point put out on this from the DoD to enlisted and contractors and the subject was picked up by regular media too a while back. Between the Images, and social networking postings, you could leave a trail of your comings and goings, when you weren’t home, etc... unless you disabled the GPS coordinate embedding on images and postings. I believe there might have been actual instances where the bad guys were able to utilize the coords from social networking posts to drop mortar rounds on certain targets.
yeah, that sounds like the article I read.