DescriptionThis research investigates mixed-mode groups. These are a growing phenomenon of voluntary associations that are Internet-established but operate on an in-person basis. Using Meetup.com as the research site, this study uses several approaches to analyze the evolution and ecology of mixed-mode groups at group and population levels. Specifically, through analysis of interviews with 34 Meetup organizers, the iterative processes of variation-selection-retention (V-S-R) were discerned, manifested in the formation and continuity of Meetup groups. Drawing on concepts from theories of collective action, the resulting consequences for growth and survival of groups were analyzed. Further, a longitudinal analysis of 100 randomly selected Meetup groups showed the V-S-R processes taking place at the population level. Consistent with the existing research on organizational ecology and evolution, the results suggest that the most relevant predictors of group survival included: the ecological factor in the form of population density; demographic factors represented by group age, profit orientation, and leadership; and external links. All were critical in predicting the survival of the 100 Meetup groups observed over 18 months. This research also addresses the impacts of mixed-mode groups. Analysis of an online survey with 171 Meetup group organizers yielded insights into the strategies used by groups as well as the external activities involving network contacts, which engendered positive outcomes at the collective level. Both internal and external strategies had significant effects on outcomes. However, the modeling results indicate that while internal strategies had direct effects on group impacts, external strategies had more circuitous and additive effects on group impacts. In unraveling the influence of different levels of mixed modality on group impacts, a multi-group analysis was conducted. The results showed that network communication played a critical role in mediating the relationship between the use of strategies and receipt of resources across high and low mixed-mode subsamples. The high mixed-mode subsample was also observed to have the flexibility of solely implementing internal strategies to generate group impacts, or using external strategies and network resources to do so. In contrast, in the low mixed-mode subsample, focusing more on different strategies alone would appear to help accomplish the desired outcomes. Building on the findings, this study has made analytical and theoretical contributions to the existing research. Practical and policy implications of this study are delineated as are the analytical and methodological limitations. Based on the findings and implications derived from this study, future directions of research are suggested.