Social Media Played Critical Role in Boston Marathon Response

As news of the blasts in Boston began to break Monday afternoon, people in the area turned to social media to share updates on what was happening and to tell their loved ones they were OK.

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Authorities and first responders used Twitter to relay real-time updates. The Boston police department confirmed the explosion in a tweet at 3:39 p.m. ET and continued to send information via tweets throughout the day.

People in the area reported losing cellphone service after the explosions. The Massachusetts Emergency Management Agency sent a

telling people to try to use text messaging instead.

"If you are trying to reach friends or family and can't get through via phone, try texting instead (less bandwidth)," the agency said.

Foursquare CEO Dennis Crowley, who was running in the marathon, sent a tweet that he was all right. "I'm ok. About 20K of us in corral just before mi 26. marker," Crowley wrote in


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Graphic images of the scene began to flood Twitter from people there.

The hashtag #PrayforBoston trended for hours after the event; as of Tuesday morning, #Boston was still trending in the U.S.

People also turned to Facebook to share updates from the scene, and those elsewhere used the platform to offer sympathy and support.

Instagram became a medium for hopeful messages, too. The hashtag #Boston was also trending on the picture-sharing platform as of Tuesday morning.