1. Department of Communication Studies, Department of Management Science and Engineering; Northwestern University; Evanston; IL; 60208
2. Department of Information Systems, Logistics and Innovation; Vrije Universiteit Amsterdam; De Boelelaan 1105, room 3A-24; 1081 HV; Amsterdam; The Netherlands
3. Department of Telecommunication, Information Studies, and Media; Michigan State University; Room 409, Communication Arts Building; East Lansing; MI; 48824-1212