There are several types of communities described in the document. Formal communities engage in joint activities and help each other, such as ecovillages and co-ops. Informal communities consist of social networks and common interests, like academic and recreation groups. Urban communities are large with diverse populations and advanced technology, while rural communities are usually smaller and produce their own food. Global communities share views on issues. Sectoral communities are non-profit groups. Social space communities are based on physical or virtual spaces where people gather.