The practice of sponsored search advertising - where advertisers pay a fee to appear alongside particularWeb search results - is now one of the largest and fastest growing source of revenue for Web search engines. We model and compare several mechanisms for allocating sponsored slots, including...

Despite substantial efforts to help consumers search in more intuitive ways, text search remains the predominant tool for product discovery online. In this paper, we explore the effects of visual and textual cues for search refinement on consumer search and purchasing behavior. We collaborate...

Within the last three years, Google has acquired YouTube and DoubleClick and has attempted to control part of Yahoo!'s search advertising business. Two of the deals have not raised antitrust concerns by competition authorities. I review these deals with a focus on consumer welfare. Consumers are...