Tracing Information Flow Online
David Liben-Nowell, Carleton College

Although information, news, jokes, and opinions circulate continuously in the worldwide social network, the actual mechanics of how a single particular "meme" spreads on a global scale have largely remained mysterious. A major challenge lies in the difficulty of acquiring large-scale data that records the diffusion of a single piece of information. In this talk, I will survey some recent computational research that studies information propagation through the digital traces of online activity. I will focus on joint work with Jon Kleinberg and Flavio Chierichetti that traces such information-spreading processes via the reconstruction of the propagation of two massively circulated Internet chain letters, one protesting the beginning of the Iraq war and one protesting budget cuts in U.S. governmental funding of public radio. Along the way, I will mention a few unexpected connections to problems and techniques from computational biology that arose in our data reconstruction.