Information Gatekeepers on the Internet and the Competitiveness of Homogeneous Product Markets
研究信息守门人（如比价网站）如何通过向企业和消费者收费，影响同质产品市场的价格分散、企业参与和社会福利，发现守门人利润最大化时价格分散存在、广告费过高且低于未广告价格。
We examine the equilibrium interaction between a market for price information (controlled by a gatekeeper) and the homogenous product market it serves. The gatekeeper charges fees to firms that advertise prices on its Internet site and to consumers who access the list of advertised prices. Gatekeeper profits are maximized in an equilibrium where (a) the product market exhibits price dispersion; (b) access fees are sufficiently low that all consumers subscribe; (c) advertising fees exceed socially optimal levels, thus inducing partial firm participation; and (d) advertised prices are below unadvertised prices. Introducing the market for information has ambiguous social welfare effects.