Digital trace data are an important resource for the study of social life and human behavior. Digital trace data document users’ interactions with digital information systems. This includes interactions on social media services – like Facebook, TikTok, or X (Twitter) – as well as interactions with devices – such as smart phones or smart speakers. This makes digital trace data into an important source for the analysis of communicative phenomena in digital media and beyond. But to realize their potential, researchers must first account for their characteristics as measures of society and behavior. This includes questions as to what phenomena they do speak directly, which can be inferred based on theorizing the links between specific data generating processes and phenomena of interest, what remains hidden, and how related uncertainty can be accounted for or even quantified.