1. School of Information, University of Michigan, Ann Arbor, USA
2. Department of Communication Studies, Northwestern University, Evanstone, USA
3. Department of Media and Communication, LMU Munich, Munich, Germany
4. Department of Computational Social Science, Cologne, Germany; GESIS - Leibniz-Institut für Sozialwissenschaften TeBlunthuis, Hase & Chan, Mannheim, Germany