The Diffusion Of Support In An Online Social Movement: Evidence From The Adoption Of Equal-Sign Profile Pictures

In March of 2013, 3 million Facebook users changed their profile picture to one of an equals sign to express support of same-sex marriage. We demonstrate that this action shows complex diffusion characteristics congruent with threshold models, with most users observing several of their friends changing their profile picture before taking the action themselves. While the number of friends played a role in the adoption dynamics, so did demographic characteristics and the general propensity of the individual to change their profile picture. We show via simulation that the adoption curve is consistent with a heterogeneous-threshold model, in which the probability of adoption depends on both the number of friends and the susceptibility of the individual.