Unprecedented uses of information and communication technology (ICT) and particularly social media (e.g., Wikipedia, Facebook, and Twitter) are occurring in times of crisis. This dissertation investigates the socio-technical practices emerging from the use of social media and how these practices help to "sustain the living heritage" of historic crises. The purpose is to provide empirical evidence on how heritage is a living and participatory phenomenon that needs to be considered when designing technology for heritage matters. The concepts of "grassroots heritage" and "socially-distributed curation" are offered as a way of interpreting heritage in the context of the participatory culture. This dissertation presents a multi-method investigation to determine what crisis narratives appeared in social media and how social media were used to sustain these narratives through curatorial activities. The first study surveys the social media presence of 111 crisis events that occurred between 1960 and 2010 to examine if and how past historically significant crisis events were being commemorated in the present day through new media. Then, ethnographic and automated collection methods were used to identify narratives appearing in the social media landscape for four crisis events that exhibited a high social media presence in the survey. The dissertation presents five meta-narratives for two crisis cases: (1) the 1984 Bhopal gas leak and (2) the 2001 September 11 attacks. One critical finding is that people sustain the heritage of historic crises in the digital world by perpetually revising narratives while adapting these messages to the new media of today. The second study critiques both the concept of "curator" as a profession as well as the concept of "curation" that is emerging from the social web to develop an initial conceptual model of curation. The final study involved the application and assessment of this initial conceptual model by analyzing the curatorial activities that produced the crisis narratives found in the first study. From this assessment, I articulate a theoretical model called "socially-distributed curation" to inform the design of future social technology. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]