We study a repeated game where a seller, who has a short-term incentive to supply low quality, is periodically matched with a randomly selected buyer. Buyers observe only the outcomes of their neighbors' games and may receive signals from them. When the buyer population is large, the seller may sell high quality even when each buyer observes her action in any given period with an arbitrarily small probability. When networking among buyers is costly, low quality is always supplied with a positive probability. For this case, we characterize an equilibrium where the seller randomizes between high and low quality.

We present a framework to evaluate the impact of digital music distribution. We set up a representative model that enables the comparative static analysis. We then interpret two empirical observations about the music industry, the sales decline and the price constancy, and fit the model to these observations. We find that, while the impact of digitalization on the producers' profits is probably negative, it may not be as severe as the observed impact on the quantity. On the other hand, the impact of digitalization on the consumer surplus is unambiguously positive. The impact on the social welfare is rather ambiguous, but numerical calculations reveal that the social welfare has increased for most parameter values. We also show that enhanced copyright protection to counteract the impacts of digitalization may have an unexpected effect on the social welfare. JEL Classification: K11; L86; O34

No abstract

We examine mixed bundling in a competitive environment that incorporates vertical product differentiation. We show that, compared to the equilibrium without bundling, (i) prices, profits and social welfare are lower, whereas (ii) consumer surplus is higher in the equilibrium with mixed bundling. In addition, the population of consumers who purchase both products from the same firm is larger in the equilibrium with mixed bundling. These results are largely in line with those obtained in the previous literature on competitive mixed bundling with horizontal differentiation. Further, we conduct a comparative static analysis with respect to changes in quality differentiation parameters. When the quality gap between brands narrows under no bundling and symmetric mixed bundling, prices and profits decrease. When quality differentiation is asymmetric across products, however, complicated effects occur on prices and profits due to strategic interdependence that mixed bundling creates.