With the increasing adoption of paid placement in search engines as an advertising strategy, firms are concentrating in using the most effective keywords. The present study attempts of explore the variations in keyword effectiveness across different keyword categories. The click through rates...

We analyze a large-scale randomized field experiment in which a search engine varied the prominence of search ads for 3.3 million US users: one group of users saw the status quo, while the other saw a lower level of advertising (with prominence of search ads decreased). Revealed preference data...