The initial response to the Indonesian Tsunami was from a handful of bloggers. This small group grew into a community which ultimately spanned the globe and played a critical role in coordinating communication and resources. A similar online community grew up in response to the Haiti Earthquake, to the Sichuan Earthquake in China in 2008, and the Yushu Earthquake in 2010 but not in response to Hurricane Katrina. The panel will explore the factors that encourage the formation of a community of practice, of interest, or of advocacy and the role of technology in the formation of natural response online communities. The response is often attributed to social computing, but is the technology simply an enabler of the natural response of communities? What factors contribute to sustaining a community after the initial disaster has passed? Are these online communities simply expanded, technology-enabled Hastily Formed Networks (HFN's)? The panelists have direct experience working and studying recent response to disasters and will draw upon that experience to highlight the similarities and differences of particular disaster responses, and share their thoughts on how and what can be done to leverage communities and technology to effectively and efficiently respond to future disasters.