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...

Auctions are among the oldest economic institutions in place---they have been used since antiquity to sell a wide variety of goods, and their basic form has remained unchanged. In this dissertation, I explore the efficiency of common auctions when values are interdependent---the value to a...

Many important phenomena (electoral competition, R&D races, lobbying) are instances of multiple simultaneous contests with unconditional commitment of limited resources. Specifically, the following game is analyzed in the first chapter. Two players compete in a number of simultaneous contests....

Efficient allocation of scarce resources is one of the central themes in economics. The essays in this thesis approach two aspects of this problem. In the first essay I consider the problem of the efficient provision of a public good with congestion in a setting with asymmetric information....