“…These groupings correspond to communities that are conventionally labelled as bands (or overnight camp groups), communities (or clans), mega-bands, and tribes (Lehmann, Lee, and Dunbar 2014), respectively. Data from Facebook, Twitter, e-mail, and massive multiplayer online games suggest that this same grouping pattern and scaling ratio occurs even in online environments (Arnabaldi et al 2015;Dunbar et al 2015;Fuchs et al 2014;Gonçalves, Perra, Vespignani 2011;Haerter, Jamtveit, and Mathiesen 2012;Pollet, Roberts, and Dunbar 2011). These structural features of communities turn out to mirror the internal structure of personal social networks (Hill and Dunbar 2003;Sutcliffe et al 2012;Zhou et al 2005) and are similar to the layering pattern found in animal species that live in complex societies (Hill, Bentley, and Dunbar 2008).…”