The authors examine how positive incidental emotion influences online search and ad click-through rates. They predict and find that although positive incidental emotion is irrelevant to the search task, it has the effect of priming emotionally congruent thoughts, which increases the likelihood that consumers will use positive emotion words as keywords in their search queries. This use of positive emotion keywords, in turn, increases the likelihood of clicking on paid search ads. Results from six studies support this prediction and the role of lower persuasion knowledge as a mechanism. Specifically, the use of positive emotion keywords in search queries reduces the likelihood that consumers will use persuasion knowledge toward sponsored content in the form of paid search ads—making them more likely to click on the ads. This examination of the role of positive incidental emotion and the use and consequence of positive emotion keywords in search queries has important implications for advertisers’ search engine keyword targeting strategies.

Digital advertising markets are growing and attracting increased scrutiny. This article explores four market inefficiencies that remain poorly understood: ad effect measurement, frictions between and within advertising channel members, ad blocking, and ad fraud. Although these topics are not unique to digital advertising, each manifests in unique ways in markets for digital ads. The authors identify relevant findings in the academic literature, recent developments in practice, and promising topics for future research.