A “community” is basically a social group sharing an environment. During most of human history, people were born into their community — their physical or social environment, (perhaps their caste or class). More recently membership in a community has become a matter of choice.
Many people choose an “intentional community” in the physical world or a “virtual community” in cyberspace. I am grateful for the privilege to choose! Groups on Facebook and “tribes,” such as Katie Feiling‘s “the Unified Tribe” are virtual communities.