as well as horizontal externalities are positive in isolation, and one would rather expect underprovision. Lastly, when …

In this paper, we undertake an in-depth inquiry into the nature of sharing externalities, and study how they affect the … market outcome. We show that the key thing for understanding sharing externalities is the interplay between two forces: the …

We investigate the effect of direct network externalities on the long- run dynamics of two-sided platforms. Two … characteristic of the two-sidedness is the existence of indirect network externalities between the two sides. How- ever, direct … externalities can also be important in one or both sides of the market. For instance, direct externalities include review systems …