Conditionally Accepted at Organization Science The Impact of Membership Overlap on Growth: An Ecological Competition View of Online Groups

The dominant narrative of the Internet has been one of unconstrained growth, abundance, and plenitude. It is in this context that new forms of organizing, such as online groups, have emerged. Yet the same factors that underlie the utopian narrative of Internet life also give rise to numerous online groups, many of which fail to attract participants or to provide much significant value. This suggests that in spite of the potential transformative nature of modern information technology, issues of scarcity, competition, and context may remain critical to the performance and functioning of online groups. In this paper, we draw from organizational ecology theories to develop an ecological view of online groups to explain how membership overlaps among online groups cause inter-group competition for member attention and affect a group's ability to grow. Hypotheses regarding the effects of group size, age, and membership overlap on growth are proposed and tested with data from a 64-month, longitudinal sample of 240 online discussion groups. The analysis shows that sharing members with other groups reduced future growth rates, suggesting that membership overlap puts competitive pressure on online groups. Our results also suggest that, compared to smaller and younger groups, larger and older groups experience greater difficulty in growing their membership. In addition, larger groups were more vulnerable to competitive pressure than smaller groups: Larger groups experienced greater difficulty in growing their membership than smaller groups as competition intensified. Overall, our findings show how an abundance of opportunities afforded by technologies can create scarcity in user time and effort, which increases competitive pressure on online groups. Our ecological view extends organizational ecology theory to new organizational forms online and highlights the importance of studying the competitive environment of online groups.