Law enforcement agencies, like many other types of organizations, are finding ways to use social media to disseminate information to the public. In fact, police agencies in larger cities are finding that their communities expect them to have an online presence on platforms such as Twitter, Facebook, and YouTube. Police departments also have begun to explore the use of social media to obtain information, especially for tactical purposes, such as gathering information about threats of mob violence, riots, or isolated criminal activity during otherwise lawful mass demonstrations. Police agencies must also consider how their own actions are reported to the public through social media. Nearly any action taken in public by a police officer may be recorded on a mobile device and instantly uploaded to YouTube or another social networking site. Many of today’s police chiefs have said that they generally advise their officers to always behave in public as if they are being recorded, because that very well may be the case. Another consideration is that crime victims and witnesses can quickly transmit information about a crime scene or criminal act out to the world, impeding a detective’s ability to control the release of information about a case. The strategic challenges of monitoring social networks and transforming huge amounts of data into actionable intelligence can be a daunting task for police agencies. As one official described it, “It is like trying to take a sip from a fire hydrant." The use of social media in policing is an issue that has only begun to emerge in the last few years, so policy appears to be lagging behind practice to some extent. In a recent survey of 800 law enforcement agencies in the United States, 88 percent of agencies reported using social media, yet only 49 percent had a social media policy.4 Some police leaders have said they find the process of developing policies helpful in improving their understanding of the issues surrounding social media. This publication is part of a series of reports on emerging issues that are being examined by the Police Executive Research Forum (PERF) with support from the Office of Community Oriented Policing Services (COPS Office). The goal of this project is to examine social media in policing from two tactical points of view: (1.) The use of social media by criminal offenders to organize or facilitate criminal events. (2.) The use of social media by law enforcement agencies to manage large gatherings of people, investigate crimes, or handle other events.