What is the effect of pre-release advertising on the demand for a product? And does the magnitude of that effect vary according to the quality of the good? We provide empirical insights into these questions in the context of the motion picture industryƯa setting in which the lion's share of advertising occurs prior to product launch. We make use of a unique, proprietary data set that covers (1) weekly television advertising expenditures for a sample of 280 movies released between 2001 and 2003, (2) weekly expectations of the market performance of those movies collected by means of a popular online stock market simulation, the Hollywood Stock Exchange, and (3) measures of the movies' inherent quality or appeal.