Gee argues, because they are sustained by common endeavors that bridge differences in age, class, race, gender, and educational level, and because people can participate in various ways accord- ing to their skills and interests, because they depend on peer-to-peer teaching with each partic- ipant constantly motivated to acquire new knowledge or refine their existing skills, and because they allow each participant to feel like an expert while tapping the expertise of others (Gee, 2004)