Online reviews could, in principle, greatly improve consumers' ability to evaluate products. However, the authenticity of online user reviews remains a concern; firms have an incentive to manufacture positive reviews for their own products and negative reviews for their rivals. In this paper, we...

This paper examines a model in which advertisers bid for "sponsored-link" positions on a search engine. The value advertisers derive from each position is endogenized as coming from sales to a population of consumers who make rational inferences about firm qualities and search optimally....

Online sources sometimes publish information that is false or intentionally misleading. We study the role of social networks and advertising on social networks in the dissemination of false news stories about childhood vaccines. We document that anti-vaccine Facebook groups disseminate false...

Increasingly detailed consumer information makes sophisticated price discrimination possible. At fine levels of aggregation, demand may not obey standard regularity conditions. We propose a new randomized sales mechanism for such environments. Bidders can "buy-it-now" at a posted price, or...

Search frictions can explain why the "law of one price" fails in retail markets and why even firms selling commodity products have pricing power. In online commerce, physical search costs are low, yet price dispersion is common. We use browsing data from eBay to estimate a model of consumer...

We investigate the "generalized second price" auction (GSP), a new mechanism which is used by search engines to sell online advertising that most Internet users encounter daily. GSP is tailored to its unique environment, and neither the mechanism nor the environment have previously been studied...

In this paper, we explore the hypothesis that an important force behind the collapse in advertising revenue experienced by newspapers over the past decade is the greater consumer switching facilitated by online consumption of news. We introduce a model of the market for advertising on news media...

Platform marketplaces can potentially steer buyers to certain sellers by recommending or guaranteeing those sellers. Money-back guarantees—which create a direct financial stake for the platform in seller performance—might be particularly effective at steering, as they align buyer and...

Ad blockers allow Internet users to obtain information without generating ad revenue for site owners; and by 2016 they were used by roughly a quarter of site visitors. Given the ad-supported nature of much of the web, ad blocking poses a threat to site revenue and, if revenue losses undermine...