We study the role of store-format choices in dynamic competition between two major chains in the U.S. discount-store industry. The aim is to measure the effect on Kmart profits of Walmart Supercenters, which combine a full-service grocery with a regular discount store. The data are a six-year...

This paper estimates a dynamic model of user behavior in a social network site using unique data on the daily login activity of a sample of members of MySpace.com. We view a social network as a stock of capital that yields a flow of utilities over time by creating interactions between the site...