Emergence of the web and cyberspace gave rise to detailed traces of human social activity. This offers great opportunities to analyze and model behaviors of millions of people. Take, for example, an examination of planetary scale dynamics of a full Microsoft Instant Messenger network that contains 240 million people, with more than 255 billion exchanged messages per month (4.5TB of data), which makes it the largest social network analyzed to date. In this University of Washington program, guest speaker Jure Leskovec of Carnegie Mellon University, focuses on two aspects of the dynamics of large real-world networks -- dynamics of information diffusion and cascading behavior in networks, and dynamics of the structure of time evolving networks.