Online Communities are found around in various formats. Popular blogs with regular readers (who also comment on posts regularly), forums and more obviously social networking sites often fall under the 'online community' definition, as can some MMORPGs (Massively Multiplayer Online Role Playing Games).
The definitive factor is a place where people communicate with each other online. Whether an e-mail list can be called an online community is questionable, whilst many online communities have certainly grown around what started out as a simple e-mail list.
You'll find a number of articles about online communities here. Another one of my favorite blogs covering the topic is Mashable.com, which, as well as talking about online communities, has its own social networking community element on the site.Powered by Sidelines