This paper develops a fairly general model of platform competition in media markets allowing viewers to use multiple platforms. This leads to a new form of competition between platforms, in which they do not steal viewers from each other, but affect the viewer composition and thereby the...

The existing literature on two-sided markets addresses participation externalities, but so far it has neglected pecuniary externalities between competing platforms. In this paper we build a model that incorporates both externalities. In our setup differentiated platforms compete in advertising...