In the past few years, YouTube and other sites for sharing video files over the Internet have vaulted from obscurity to places of centrality in the media landscape. The files available at YouTube include a mix of user-generated video and clips from network television shows. Networks fear that...

Recent literature notes that when quality is produced with fixed costs, a high quality firm can undercut its rival's prices and may find it profitable to invest more in quality as market size grows large. As a result, a market can remain concentrated even as it grows large. When quality is...

Free entry into markets with decreasing average costs and differentiated products can result in an inefficient number of firms and suboptimal product variety. Because new firms and products draw their customers in part from existing products, concentration can affect incentives to enter as well...

When a product's product provision entails fixed costs, it will be made available only if a sufficient number of people want it. Some products are produced and consumed locally, so that provision requires not only a large group favoring the product but a large number nearby. Just as one has an...