Affinity groups, as they’re often called within the study of social movements, have been a common feature of grassroots political organising in recent years. “We have seen this developing over time, in many contemporary movements – where people are valued for their expertise and what they can bring within the larger movement,” says Bart Cammaerts, a professor of politics and communication at the London School of Economics.

For XR itself, the model seems to have worked, if anything from a numerical standpoint. As academics Douglas McAdams and Ronnelle Paulsenfound in 1993, knowing someone who is involved in social movements is one of the strongest predictors of recruitment into that same movement.