NET Institute* www.NETinst.org Working Paper #10-18 September 2010 Is Oprah Contagious? Identifying Demand Spillovers in Product Networks Eyal Carmi Tel-Aviv University Gal Oestreicher-Singer Tel-Aviv University Arun Sundararajan Stern School of Business, NYU * The Networks, Electronic Commerce, and Telecommunications (“NET”) Institute, http://www.NETinst.org , is a non-profit institution devoted to research on network industries, electronic commerce, telecommunications, the Internet, “virtual networks” comprised of computers that share the same technical standard or operating system, and on network issues in general.