Paul-Olivier Dehaye is the co-founder of PersonalData.IO, a service that helps individuals regain control over their personal data. He also enjoys working with journalists, explaining cutting-edge societal issues in the personal data ecosystem. He has for instance done a lot of the research behind the most widely shared article on German social media in 2016, exposing and explaining the data-driven psychometric profiling used during the US election (English version). In parallel, he works as a mathematician at the University of Zurich, as part of the large European collaboration OpenDreamKit. The project is building an interoperable toolkit to help computational mathematicians in their everyday research, by facilitating the collaborative handling of mathematical data, knowledge and software.