This paper presents a case study of a very recent man-made crisis in Norway on 22 July, 2011, during which a single person first detonated a bomb in downtown Oslo and then killed 69 young people on the island of Utøya. It proposes a novel way of conceptualizing the public contribution to mobilization of resources using microblogging, particularly tweeting. By examining aspects of public and professional response to this crisis, the notion of peripheral response is developed in relation to emergent forms of agile and dialogic emergency response. Through examining the distributed efforts of responding to the crisis, the paper also revisits situation awareness and reflects upon the dynamic and constantly changing environment that social media and crises inhabit together.