1. Weizenbaum Institute for the Networked Society, Freie Universität Berlin, Berlin, Germany
2. Amsterdam School of Communication Research, University of Amsterdam, Amsterdam, Netherlands
3. Department of Methodology and Statistics, Utrecht University,Utrech, Netherland
4. Hussman School of Journalism and Media, University of North Carolina at Chapel Hill, Raleigh, North Carolina, USA
5. Department of Communication, Stanford University, Stanford, USA
6. Departments of Pediatrics and Medicine, Stanford University, Stanford, USA