This paper estimates the importance of network effects in the market for Yellow Pages. I estimate three simultaneous equations: consumer demand for usage of a directory, advertiser demand for advertising and a publisher's first-order condition (derived from profit-maximizing behavior)....

With an emphasis on peer-produced content and collaboration, Wikipedia exemplifies a departure from traditional management and organizational models. This iconic "project" has been variously characterized as a hive mind and an information revolution, attracting millions of new users even as it...