- If you're on vacation (or in a secret military location), don't post about it until after you get back (or to a safe, non-secret military location). Posting pictures and updates while you're thousands of miles away from your home advertises that you're...thousands of miles away from your home.
- Monitor what your friends say to you and about you on Facebook. In your Privacy settings, it's a good idea to turn on the "review posts" feature, which lets you approve (or disapprove) posts your friends want to tag you in before they automatically appear on your timeline. To turn on this feature, go to Privacy > Timeline and Tagging > Review posts friends tag you in before they appear on your timeline, and turn it "On."
- Be careful about what your photos say. Many smartphones automatically geo-tag photos, so it's a good idea to turn this off, if possible. To turn off geo-tagging on an iPhone, go to Settings > Location Services > Camera, and turn the Location Services "Off" for the camera. To turn of geo-tagging on an Android phone, open up your camera, go to Camera settings > Store location, and make sure this is turned "Off."
As I said earlier, the easiest way to avoid this type of privacy mishap is to only friend people you actually know in real life. Still, it's a good idea to take these precautions--after all, you never know which of your real-life Facebook friends may have left their account open on a public computer somewhere.
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