Online communities are any group of people who communicate with each other via computers.
Online communities are supported by listservs, bulletin boards, chats, MUDs, MOOS or combinations of these software programs along with web pages. Some communities are complex with highly integrated sites, others comprise just a single bulletin board or listserv, some support geographical communities, others are purely virtual, some have real concerns while others are fantasy worlds. There are a wide variety of communities focusing on many topics including health, religion, education, culture, community, sports, pets, children, old age, professional issues, games and so on. Thousands of online communities exist and more come online everyday. Two particularly big growth areas are communities for health problems and electronic commerce.