Collaboration in art and in science: Approaches to attribution, authorship and acknowledgement. Invited presentation, Edinburg Napier University, March 2011.

E pluribus unum? The paradox of a postmodern profeession. Keynote address, International Online Meeting, London, December 2009.

Never too many cooks; The epistemic value of collegiality. Invited lecture, University of Washington, Seattle, January 2009.

Toward a Rhopography of Scholarly Communication. Keynote address, USE-2008, University of Oulu, Finland, June 23-25, 2008.

Eros Unbound: Pornography and the Internet. Invited seminar, Oxford Internet Institute, University of Oxford, October, 2006.

The socio-technical ties that bind: Using paratextual analysis to explore the epistemic significance of collegialtiy. Invited seminar, City University, London, September, 2006.

Authorship and Attribution; Access and Attention. Invited lecture, University of California at San Diego, November 2005.

What paratexts can tell us about the social and material bases of scholarly interaction. Material Cultures Conference, Edinburgh University, July 2005.

The Many Hands of Science: An Overview of Collaboration and Co-authorship Trends. Invited lecture, University of Montreal, Canada, February 15, 2005.

Scholars and scripts, eyeballs and epistemes; What it means to publish. Distinguished Seminar Series, OCLC, Columbus, Ohio, May 17, 2004.

Scholarly communication and epistemic cultures. Keynote address. Scholarly Tribes and Tribulations: How Tradition and Technology are Driving Disciplinary Change. ARL. Washington, D.C. October 17, 2003.

Netcentric terrorism: The organization of intelligence services in the network age. Public Lecture, University of Oxford (St. Anthony's College), UK, May 7, 2003.

Visible, less visible, and invisible work. Invited Presentation, Manchester Metropoliton University, Manchester, UK, October 25, 2002.

The virtues, vices, and vicissitudes of digital life. Keynote address, VIII Conferencia Internacional de Bibliotecologia "Biblioteca Digital: Perspectives, Experiencias y Opportunidades", October 24-26, 2001, Santiago de Chile.

Bibliometrics and beyond: some thoughts on webometrics and influmetrics. Invited presentation, Freedom of Information: The Impact of Open Access on Biomedical Research. July 6-7, 2000. New York Academy of Medicine, New York, USA.