TeBlunthuis, Nathan, et al. "No community can do everything: why people participate in similar online communities." Proceedings of the ACM on Human-Computer Interaction 6.CSCW1 (2022): 1-25.

This study explains the existence of overlapping online communities within platforms like Reddit through 20 interviews with active subreddit participants. It finds that diverse needs, including specific information, socialization, and attention, drive the formation of specialized communities within broader topics. These specialized communities vary in size, focus, and rules, offering a wider range of benefits than a single community could.