Though not entirely astonishing, this new research finding is nonetheless fascinating:
Some turnover may be necessary to allow new members to join. Online communities are not technically limited to a finite size, but people tend not to join once the membership or communication levels are perceived to be too high. Groups that are isolated from outside perspectives can develop biases and insular thinking that leave them susceptible to overconfidence about the group’s ability to collaborate effectively. Thus, some turnover might be necessary to create an influx of unique contributors with new ideas, skills, and information.
In a recent HBR blog post, in which this paper was reviewed, the authors conclude that mature online communities will increasingly:
need to better to (sic.) balance policies aimed at retention with those aimed at recruitment and mentoring.