New paper on how ads compete for consumers using information design

This paper tackles the classic problem of how advertisers should strategically disclose information to consumers who search sequentially. The authors extend the foundational Anderson and Renault model into a competitive environment: multiple horizontally differentiated advertisers (senders) compete for the attention and purchase of a single unit-demand consumer (receiver). The receiver follows Weitzman's Index Algorithm to decide when to stop searching and buy, making the problem a game of information design.

The researchers introduce a duality-based method to verify whether a given information strategy is a best response against competitors. They prove the existence of an equilibrium when prior distributions have no mass, though such equilibria can be complex. Under monotone increasing densities, they fully characterize symmetric equilibria, offering economic intuition behind the structure. This work bridges game theory, information economics, and search theory, with implications for ad tech, recommendation systems, and online marketplaces.