As the horrific attacks in Paris unfolded in November, the world united to support people in the City of Light using the hashtag #PrayForParis. The outpouring of support was also shared 70 million times on Instagram. More poignantly, Parisians, who were safe at home, used the hashtag #PorteOuverte open door on Twitter in the immediate aftermath of the attacks, as a way to offer shelter to others around Paris who may need a place to stay.For more info: http://www.msnbc.com/msnbc/how-social-media-played-role-the-aftermath-the-paris-attacks