Media diversity, advertising, and adaptation of news to readers’ political preferences

In this paper, it is analyzed how advertising can affect media diversity when news firms can adapt news to readers’ political preferences. In particular, in the model news firms can choose between a single- and a multi-ideology strategy (a point on the Hotelling line and a line segment, respectively). It is shown that the size of the advertising market is determinant for the equilibrium of the news market. When the advertising market is small, news firms maximally differentiate their political offers and do not adapt news to readers’ political preferences (single-ideology strategy). When the advertising market is large, news firms minimally differentiate their political offers and do adapt news to readers’ political preferences (multi-ideology strategy).