The network mechanisms behind the sharing of online traffic among three platforms in two different categories: a longitudinal analysis of audience overlap among social and communication platforms

Due to the abundance of media options, users of one digital platform are often users of others in the same or a different category, leading to complex inter-platform interdependence on a broader scale. This study examines triadic platform interdependence, which links three digital platforms through audience overlap, from an organizational network perspective. Using Comscore's unobtrusive tracking data, the study aims to elucidate the network mechanisms behind the sharing of audience members among two social platforms and one communication platform, as well as among two communication platforms and one social platform. The results of the longitudinal network analysis of Comscore's audience tracking data show that audience overlap with a third social platform is positively associated with an increased probability that two communication platforms will share an audience. In addition, a shared audience between two social (or communication) platforms will positively predict their audience overlap with a third communication (or social) platform at a later point in time. The findings provide new insights into (1) network closure among three media nodes in two different categories and (2) the sequential development of media commensalism and symbiosis in the platform ecosystem.