While various definitions have been offered in the literature, a simple definition is adopted for the purposes of this chapter:
A virtual community is a population of individuals with shared or complementary interests who interact across a host platform.
Viewed from a socio-technical system perspective, our definition makes explicit the social aspect and the technical aspect. The social aspect is the population of individuals and their interests and needs. In some cases, the members of the population may have a single shared interest as in a socializing community where the members are generally seeking friendship and a social experience. In other cases, the population may consist of individuals with two different but complementary interests or needs, as with a knowledge sharing community where some members have an interest in providing knowledge while other members have a need to seek knowledge.1
The technical aspect of the virtual community is the web-based host platform which is provided by a hosting organization. We view this host platform as including not only the enabling technologies, such as wikis, blogs or databases, but also the rules and policies which govern the behavior of community members. The host organization will typically provide some general policies while individual community managers will often provide more specific policies geared to the needs of their particular community.
Combining a population and a platform, a set of interactions will emerge and in some respects the community itself is defined by this set of interactions. In this context, the notions of “community” and “interaction” are broadly interpreted and can involve either direct interactions among individuals (e.g. as in threaded conversations) or indirect interactions through the collective creation, modification, and use of persistent digital goods (e.g. as in interactions through a digital repository such as the Wikipedia). Taken together, the technology and policy components of the platform provide a protocol of interaction for the virtual community. This protocol essentially represents a set of affordances and constraints which can have a significant influence on the nature and success of the community that emerges.