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...

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...