Prof. Sebastian Stier, Scientific Director of Computational Social Science at GESIS and Professor of CSS at the University of Mannheim, discusses how web tracking data can inform social science questions. We discuss the data structure of web browsing data, how it is collected, and the types of incentives used to recruit participants. Prof. Stier also shares his insights and research integrating web browsing data with survey data, as well as how LLMs are opening up new methodological avenues in simulated data.