Many facts are learned through the intermediation of individuals with special access to information, such as law enforcement officers, employees with a security clearance, or experts with specific knowledge. This paper considers whether societies can learn about such facts when information is...

We model an online display advertising environment in which "performance'' advertisers can measure the value of individual impressions, whereas "brand" advertisers cannot. If advertiser values for ad opportunities are positively correlated, second-price auctions for impressions can be...