for different participants and show how managers can influence outcomes with usability and sociability interventions, while addressing security versus freedom trade-offs.

National Initiative for Social Participation

The collection of articles published in this special issue emerged from the grassroots efforts of participants from academia, private industry, and government who have come together to propose a National Initiative for Social Participation.

An initial meeting held at the University of Maryland in spring 2009 solidified the formation of a core group and the presentation of a report 8 that subsequently led to National Science Foundation support for workshops hosted by the Palo Alto Research Center in December 2009 and the University of Maryland in April 2010 ( www.tmsp.umd.edu). The aim of these workshops was to produce a roadmap for national research and development,Research Center. His research interests are human-information interaction and theories of complex cognition and social interaction. Pirolli is a Fellow of the AAAS, American Psychological Association, Association for Psychological Science, ACM SIGCHI Academy, and National Academy of Education. Contact him at peter.pirolli@parc.com.

Jenny Preece is a professor and dean of the College of Information Studies at the University of Maryland. Her research interests are online communities and social media, particularly what motivates participation. Contact her at preece@umd.edu.

Ben Shneiderman is a professor of computer science and founding director of the Human-Computer Interaction Lab at the University of Maryland. His research interests are HCI, information visualization, and social media. Shneiderman is an AAAS Fellow and a member of IEEE, the ACM, the ACM SIGCHI Academy, and the National Academy of Engineering.