Dr. Gerlitz is Professor of Digital Media and Methods at the University of Siegen and Co-Director of the Graduate School 'Locating Media'. Her visit to CIM is part of her research project "Numbering Life. Measures and Metrics in Digital Media”. This project is funded by the Dutch Council for Scientific Research (NWO) and explores the productive and performative capacities of social media metrics. It involves collaboration with Celia Lury on cultures of quantification and with Michael Dieter on app metrics. A second aim of the fellowship is to continue an ongoing collaboration with Noortje Marres, who is Mercator fellow of the University of Siegen-based collaborative research centre “Media of Cooperation”. Part of this collaboration includes the joint research project “YouTube as a Test Society”.