Much of our routine online activity leaves behind so-called 'traces,' or electronic records of those actions. These traces have attracted the attention of social, behavioral, and computational scientists, legal scholars, and marketing experts, among others. As people increasingly incorporate web-based technologies into their daily lives, there are myriad opportunities to examine human behavior from those traces. How can we use these data, and what can they tell us about human social behavior? In this talk I share some of the tools, methods, and applications from my research on these web-based records of activity. Specifically, I demonstrate their application to social behavioral research contexts, with an emphasis on extracting and studying the social networks that emerge from these data.