Group Hug: Platform Competition with User-Groups

Abstract

We consider platform competition in the presence of small users and a usergroup. One platform enjoys a quality advantage and the other benefits from favorable beliefs. We study whether the group mitigates the users' coordination problem i.e., joining a low-quality platform because they believe that other users would do the same. We find that when the group is sufficiently large to facilitate coordination on the high-quality platform, the group may choose to join the low-quality one. When the group joins the more efficient platform it does not necessarily increase consumer surplus. Specifically, a non-group user benefits from a group with an intermediate size, and prefers a small group over a large group. The utility of a group user is also non-monotonic in the size of the group.