In this introduction, we aim to examine how data science and social science can mutually help each other when it comes to analyzing the political Web. On the one hand, by developing (partially) automated tools for collecting and analyzing digital corpora, data scientists can provide valuable help to social scientists who have to deal with big data. Reciprocally, through their feedback on their experience and their critical uses of these tools, social scientists may enrich the results of data science. The structured methodologies of both disciplinary fields can thus enrich one another when building the research corpora, when analyzing the data and when extrapolating from the results. For each of these research stages, we aim to show what is heuristically and technically specific about research fields in digital spaces, what kind of methodological and epistemological problems they may raise, and how data science can provide solutions.