When the Internet was in its infancy, it was a community in itself. The fact that a person had access to the Internet was enough of a distinguishing characteristic. As the number of users grew, access alone ceased to be enough to provide that sense of community. So other communities naturally grew up wherever people shared interests. Those interests could be anything from speaking German to using the Unix operating system, so long as enough people shared them.
Communities begin to work once they achieve critical mass'.
Just as a party won' t get into full swing until there are a certain number of people at it and this number will be different depending on whether the party is being held in a hotel room or a concert hall so with a community. The host of the party has to make sure there is a nucleus of people there, so that guests have something to arrive to. The first guests might be tempted by dinner or extra drinks, or they may just be loyal friends of the host. Early Internet communities occurred naturally and needed only a small number of people to achieve critical mass. Nearly all these natural' communities are now served.