Sachdev, Vishal2008-08-082011-08-242008-08-082011-08-242008-08-08December 2http://hdl.handle.net/10106/907With the trend towards social interaction over the Internet and the popularity of websites such as Myspace, Facebook and Youtube among others, practitioners and researchers are motivated to explain the sudden surge in user interest, in a phenomenon that we term, Social Computing. We seek to research the question: "Why do people engage in Social Computing?" The motivation is to determine some of the underlying human psychological factors that are driving this phenomenon. Towards this end, we propose a reformulation of the interactivity construct by suggesting new dimensions of interactivity that are unique to social computing. With this reformulated interactivity construct, we conduct an exploratory study using the need fulfillment lens provided by the Self Determination Theory. We assess if interactivity, in its richer formulation, influences need fulfillment, which in turn leads to higher levels of self-determined motivation. We also evaluate the impact of the latter on intentions for continued use and actual use of these websites. The results largely support the hypothesized model.ENPh.D.