This article by Timothy Butler and David Coleman discusses models of collaboration. It focuses on ways to define collaboration based on group size and level of interaction. The five categories they define are:
Here's an excerpt regarding the "Community" model's characteristics:
Members have common interest, affinity, or goal Members of the community are often self-grouping, Members seek to share information, Members seek to further their understanding of the practice or area of interest, Membership is loosely controlled, Membership must be relatively large to be self-sustaining (new content is always needed) Large communities are often moderated, facilitated or edited All members are encouraged to both read and write content, and Most members find value in just reading. Contributors are usually around 10% of the community population Most of the interactions are asynchronous, but over the last few years “chat�? communities have sprung up that utilize IM as the interaction media instead of threaded discussions. Rules of engagement, or appropriate behaviors for the community are often well defined
Via: Online Facilitation