Group Hug: Platform Competition with User Groups

We consider platform competition for small users and a user group. 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 a group that can facilitate coordination on the high-quality platform may choose to maintain the dominance of the low-quality one. Users’ utility is non-monotonic in the proportion of the group.