In e-commerce, where information collection is essentially costless and geographic location of traders matters very little, fierce competition between providers of similar services is expected. We consider a model where two e-commerce intermediaries (internet shops) compete for sellers. We show...

We consider a dynamic auction environment with a long-lived seller and short-lived buyers mediated by a third party. A mediator has incomplete information about traders' values and selects an auction mechanism to maximize her expected revenue. We characterize mediator-optimal mechanisms and show...