Economic models of information systems: Internet auctions and information gatekeepers.

摘要

In this thesis, we study two important features of the marketplace based internet economy-the emergence of information gatekeepers and the use of auction-like mechanisms to allocate and price goods sold on the internet.; The first essay “One Auction or Two? Auction with Multiple-units” discusses the application of sequential sale of multi unit auctions. We analyze the case where both the auctioneer and the bidders are impatient, and find that whether or not to use sequential auctions largely depends on the intensity of market competition. We also explore the problem of whether or not the auctioneer should tell bidders how many items are available for the auction.; The second essay “Paid Placement in Information Gatekeepers” analyzes the practice of paid placement in information gatekeepers, where the gatekeeper biases its outputs to favor certain providers who pay it a placement fee. In addition, to get a better under standing of how different search engines are using paid placement strategies, we model in chapter 4 several paid-placement ranking strategies and compare their revenues via simulation.; But these are only simulations, which can identify which mechanism is “better”, without finding out which is the “best”. In the third essay, “Optimal Allocation Mechanisms When the Ranking of Bidders Valuations is Common”, we study the following problem: buyers (content providers) compete for positions offered by the seller (search engine). While each buyer's valuation for each position is private and independent of other's valuation, the ranking for these positions is common among all the buyers. I identify the optimal mechanisms to allocate the positions under four different cases, and examine the existence of efficient incentive compatible mechanism (subject to the reserve price).