We develop a model with many advertisers (products) and many advertising markets (media). Each advertiser sells to a different segment of consumers, and each medium is targeting a different audience. We characterize the competitive equilibrium in the advertising markets and evaluate the implications of targeting. An increase in targeting leads to an increase in the total number of consumer-product matches, and hence in the social value of advertising. Yet, targeting also increases the concentration of firms advertising in each market. Surprisingly, we then find that the equilibrium price of advertisements is first increasing, then decreasing, in the targeting capacity. We trace out the implications of targeting for competing media. We distinguish offline and online media by their targeting ability: low versus high. As consumers’ relative exposure to online media increases, the revenues of offline media decrease, even though the price of advertising might increase.