A Simple Model of Search Engine Pricing
研究垄断搜索引擎如何通过设定每次点击价格来最优地决定搜索池中企业的平均相关性，发现搜索引擎可能故意设置低价以吸引低相关性广告商进入。
We present a simple model of how a monopolistic search engine optimally determines the average relevance of firms in its search pool. In our model, there is a continuum of consumers, who use the search engine’s pool, and there is a continuum of firms, whose entry to the pool is restricted by a price‐per‐click set by the search engine. We show that a monopolistic search engine may have an incentive to set a relatively low price‐per‐click that encourages low‐relevance advertisers to enter the search pool. In general, the ratio between the marginal and average relevance in the search pool induced by the search engine’s policy is equal to the ratio between the search engine’s profit per consumer and the equilibrium product price. These conclusions do not change if the search engine charges a fixed access fee rather than a price‐per‐click.