摘要：These studies examine the influence of group size and the passage of time on two characteristics of online communities: dispersion of participation in group discussions and active member turnover from month to month. We used multilevel analysis to examine the dynamics of user contributions to discussions on Reddit, a popular website that hosts large-group discussions, across 30 groups over 6 years. As groups grow in size, participation becomes more highly concentrated among fewer members while turnover decreases. As time passes, participation becomes more widely dispersed while group member turnover increases. An increase in group member turnover appears to be the result of both a maturation effect (as each group ages, turnover increases) as well as a cohort effect (groups formed at a later date have higher turnover than groups formed earlier). We can conclude from these results that as time progresses and groups become larger, they become less community-like, but in different ways.
