The capacity to capture behaviour through the ‘digital footprint’ that people generate as a by-product of their everyday activities has the potential to transform the practice of empirical social science. The chapter examines how new tools for data collection and analysis make it possible to exploit this data. It focuses on the development of the Digital Replay System (DRS), a software system that enables researchers to combine the data contained in digital records with more traditional and established forms of social science data, such as audio-visual recordings and transcriptions.