The Role of Social Networks in Information Diffusion

TL;DR

This study uses a large-scale field experiment to quantify how social networks influence online information spread, highlighting the significant roles of both social signals and weak ties in dissemination.

Contribution

It provides empirical evidence on the causal impact of social signals and distinguishes the roles of strong and weak ties in information diffusion.

Findings

Exposed individuals are more likely and quicker to share information.

Weak ties are responsible for spreading novel information.

Strong ties are more influential on an individual level.

Abstract

Online social networking technologies enable individuals to simultaneously share information with any number of peers. Quantifying the causal effect of these technologies 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.