Evans and Schmalensee argue that in a two-sided network market, it is justified for one side to pay more than the other side. The reason they give is that it often; may cost more to provide the service to one side than the other often; may be necessary to get the side that doesn't value the service as much on board never; is inefficient to charge one side more than the cost of providing them the service never: is not fair to the side that pays more