2007 – present. Professor, Department of Communication, University of Illinois at Urbana-Champaign. (Appointment also as Senior Research Scientist, National Center for Supercomputer Applications, University of Illinois at Urbana-Champaign.
2004 – 2007. Research Professor, Institute of Communications Research, University of Illinois at Urbana-Champaign. (Appointment also as Senior Research Scientist, National Center for Supercomputer Applications, University of Illinois at Urbana-Champaign.
2000 – 2004. Research Professor, Institute of Communications Research, Graduate School of Library and Information Science, University of Illinois at Urbana-Champaign. (Appointment also as Senior Research Scientist, National Center for Supercomputer Applications, University of Illinois at Urbana-Champaign.
1999– 2000. Research Associate Professor, Institute of Communications Research, Graduate School of Library and Information Science, University of Illinois at Urbana-Champaign. (Appointment also as Senior Research Scientist, National Center for Supercomputer Applications, University of Illinois at Urbana-Champaign.
1994–1998. Associate Professor, School of Journalism and Mass Communication, University of Wisconsin-Madison.
1988–1994. Assistant Professor, School of Journalism and Mass Communication, University of Wisconsin-Madison.