The last decade has witnessed the remarkable transformation of social networks in which people communicate and associate with one another via the Internet. While the popular perception of the Internet is more of a communication medium, the ramification of the Internet is far beyond that. Its significance lies in its capability of keeping people connected. Since its inception, the connectivity enabled by the Internet allows scientists geographically separated to establish a virtual community (VC) in which they distribute research findings, discuss research issues and share research interests. The deregulation of the Internet in early 1990s kindled the booming of VCs with a variety of interests. Research in VCs has been extensive; nevertheless, no one single definition of VCs has been commonly agreed upon and accepted by researchers (Lee, Vogel & Limayem, 2003; Jones, 1997; Liu, 1999). For example, Hagel and Armstrong (1997) adopted the technological deterministic perspective and defined VC as a computer-mediated space that aggregated member-generated content and correspondences, while Rheingold (1994) placed emphasis on the on-going discourse and social-psychological elements. As the debate of definition continues, instead of proposing another one, several researchers adopted an approach to characterizing VCs as follows (Wang, Yu, & Fesenmaier, 2002): 1. Members share common goals, needs and interests 2. Members engage in repeated interaction and participation 3. Members have access to resources, including information, support and services 4. Members share social conventions, language and protocols. We follow this approach in the article. Research in VC has been conducted in various areas, such as marketing (Maclaran & Catterall, 2002) and tourism (Wang, Yu, & Fesenmaier, 2002) from different perspectives, such as sociocultural (Zucchermaglio & Talamo, 2003) and philosophical (Mowbray, 2001). It is generally agreed that the critical mass of participation is requisite for success of a VC (Hagel & Armstrong, 1997; Roberts & Fox, 1998). We contend that the critical mass of a VC depicts the status quo of the community, and might not be sufficient for its sustainability. Instead, we propose the concept of sustainability of VCs and discuss factors that may affect it.