Historically, the U.S. advertising industry has been experiencing enormous movements as a result of rapid advances in the media technology and the business cycle. In this paper, we study the historical behavior of the U.S. advertising industry, correcting for inflation. We find that the introduction of new media cause structural breaks in the mean growth rates of advertising expenditure for the incumbent media. In addition, we find that random components of media advertising spending follow a long-term equilibrium where the cross-elasticities across newer and older media can show substitution or complementarity patterns depending on the type of audience. We examine the influence of the economic conditions on the aggregated advertising expenditure, and on each media spending. We also measure the impact of the recent takeoff in mobile advertising.