This article studies competition between different types of ad-funded platforms attracting consumers with free services. Consumers often find advertisements a nuisance on such platforms. We study how under a competitive setting platforms balance the tension between attracting consumers and rent...

In this thesis, we study two important features of themarketplace based internet economy-the emergence of informationgatekeepers and the use of auction-like mechanisms to allocate andprice goods sold on the internet.The first essay ``One Auction or Two? Auction with Multiple-units"discusses the...