A. Michael Spence was awarded the 2001 Nobel Prize for Economics. He is Professor Emeritus of Management in the Graduate School of Business at Stanford University where he served as dean throughout the 1990's. He is also a partner at Oak Hill Venture Partners. Prior to joining Stanford, Spence served as Professor of Economics and Business Administration and Dean of Arts and Sciences at Harvard University. Garth Saloner is the Jeffrey S. Skoll Professor of Electronic Commerce, Strategic Management, and Economics at the Graduate School of Business at Stanford University, where he headed the Strategic Management group through the 1990's and where he now directs the Center for Electronic Business and Commerce.