Turnover is commonplace in many online groups because of low barriers of entry and exit. In offline settings, turnover can have a negative impact because of reduced attachment to the group as an entity. However, in an online setting, turnover in terms of changes in the visible membership of a group may have a very different impact. Online only a limited amount of information about members and their activities is observable; in particular, it is easier to see the behavior of the subset of members who are active than the potentially larger set who are not. In this paper, we describe an experiment examining the influence of visible membership turnover on commitment to an online group. Our results suggest that increased turnover in an online group may increase social presence, creating perceptions of liveness, in turn leading to increased levels of participation in the group. However, this result holds primarily for groups with a common identity, suggesting that attention to behavior of others may be stronger when people share an identity with those others. Our results extend understandings of attachment in an online setting as well as theory about social tuning.

The existence and survival of online communities depends upon the commitment and retention of their members. This paper compares alternative ways of designing online sites to increase member commitment. We report the results of two experiments conducted within a Facebook game application. The results show that designs can increase commitment and retention of players either by visually highlighting individual members, or by emphasizing the community as a whole. These designs influence commitment through different routes.