Raytheon Riot is software that can predict your location using social media data. As revealed by The Guardian newspaper, Raytheon Riot (Rapid Information Overlay Technology) gathers data from websites including Facebook, Twitter and Foursquare and analyzes it to among other things predict where you will be at a given time. The software doesn't just use location check-ins but also location data that is embedded in photographs uploaded from smart phones. Based on those sources Raytheon Riot uses data mining to identify patterns and predict future behavior. Oh, and in case you didn't know, Raytheon is a U.S. defense contractor.
Here a video demonstrating the Raytheon Riot software's capabilities:
If you don't want people to be able to analyze and track your movements you shouldn't make posts that reveal your location. Privacy settings should help limit someone from using software like Raytheon Riot to analyze your life, but you are always safer if the data is not online at all. If you must post your location and upload photos you may want to at least vary your schedule to avoid potential stalking.
The more data you post online the more likely some of it can be used to harm you in someway. Always think before you post.
If this interests you may also want to read how Facebook Graph Search allows other Facebook users to profile you based on what you've liked.