The role of social networks in information diffusion

TLDR

Online social networking technologies enable individuals to simultaneously share information with any number of peers, and quantifying their causal effect on dissemination requires identifying influence pathways and counterfactual propagation without social signals. The study investigates how strong versus weak ties influence online information diffusion. The authors conduct a large‑scale field experiment randomizing exposure to friends’ sharing signals among 253 million users to study diffusion. Exposure to friends’ sharing signals increases both the likelihood and speed of information spread, and although strong ties are individually more influential, the sheer abundance of weak ties drives the majority of novel information propagation, indicating weak ties play a dominant role online.

Abstract

Online social networking technologies enable individuals to simultaneously share information with any number of peers. Quantifying the causal effect of these mediums on the dissemination of information requires not only identification of who influences whom, but also of whether individuals would still propagate information in the absence of social signals about that information. We examine the role of social networks in online information diffusion with a large-scale field experiment that randomizes exposure to signals about friends' information sharing among 253 million subjects in situ. Those who are exposed are significantly more likely to spread information, and do so sooner than those who are not exposed. We further examine the relative role of strong and weak ties in information propagation. We show that, although stronger ties are individually more influential, it is the more abundant weak ties who are responsible for the propagation of novel information. This suggests that weak ties may play a more dominant role in the dissemination of information online than currently believed.