A robbery occurs at a local business. When the robbery occurs, the police department immediately sends out a Twitter announcement notifying subscribers of the crime and asking them to be on the lookout for the suspects. Intelligence analysts begin checking other social media sites for subscribers who may have "checked in" near the crime. They find several people have checked in at businesses in the area using Facebook, Yelp and Four Square. Analysts send text messages to these people, who are immediately on the lookout for the suspects. Several quickly report suspicious activity and take...