The Dunbar number encapsulates the common-sense notion that humans would have evolved with an upper-bounds on the number of people to whom we can relate. Taken seriously, this cognitive limit on our ability to maintain social relationships has profound implications. There are obvious reasons for concern relating to our (mis)behaviour on social networks. Then there are less blatant issues to do with our ability to make sense in a world awash in opinions, information, and misinformation.