An eCommunity is a community of people sharing common interests, ideas, and feelings over the Internet or other collaborative network. Originally referred to as Virtual Community, a term coined by Howard Rheingold, who created "The Well", one of the first major Internet communities. In his book, The Virtual Community (fully available online), Rheingold defines eCommunities as social aggregations that emerge from the Internet when enough people carry on public discussions long enough and with sufficient human feeling to form webs of personal relationships in cyberspace.

The original vision of on-line communities dates back to 1968. In an article published in Science and Technology in April 1968, J.C.R. Licklider and Robert Taylor wrote: "What will on-line interactive communities be like? In most fields they will consist of geographically separated members, sometimes grouped in small clusters and sometimes working individually. They will be communities not of common location, but of common interest. In each field, the overall community of interest will be large enough to support a comprehensive system of field-oriented programs and data." What may be the first online community was developped as PLATO in the early 60s. Before the Web, eCommunities existed on bulletin board services (BBS), and many still do. Some eCommunities or facilitators of them use the metaphor of a coffee house or something similar to help users visualize the community.

eCommunities might be thought of as subgroups within Marshall McLuhan's notion of cyberspace as a "global village." In general, there are two kinds of communication among eCommunity members: message postings and real-time chat. Usenet newsgroups are an example of the former. Many Web sites, such as Facebook.com, foster subject information exchanges. For real-time chat, Internet Relay Chat (IRC) is a system used by many Web sites that foster eCommunities. New software allows the creation of 3D environments to develop new types of eCommunities. The fastest growing is Second Life.