Standard media economics models imply that increased platform competition decreases ad levels and that mergers reduce per-viewer ad prices. The empirical evidence, however, is mixed. We attribute the theoretical predictions to the combined assumptions that there is no advertising congestion and...

We extend the theory of advertising as a quality signal, using a model where an entrant can choose to advertise by comparing its product to that of an established incumbent. Comparative advertising, comparing quality of one’s own product to that of a rival’s, empowers the latter to file for...