Social media plays an important role in responding to disasters and emergencies. The document discusses several case studies where social media was used during the 2013 Boston Marathon bombing, the 2011 Virginia earthquake, the crash of Asiana Airlines Flight 214, the H7N9 influenza outbreak, Superstorm Sandy, a 2013 building collapse in Philadelphia, floods in Alberta Canada in 2013, and recovery efforts after Sandy. The author concludes that social media is a valuable tool for disseminating information during incidents, emergencies, and disasters.