enues on these lower-cost books. The trend of distributing movies and television shows over the Internet also has the potential to disrupt an established industry. Streaming these products via the Inter- net rather than over cable TV networks offer opportunities for online providers to profit, but it has the potential to diminish revenues for cable TV and content providers. Introduction Surveys already indicate that an increasing number of people under the age of 25 watch less television every year. Rather, they watch programs online and spend time on computers, participating in social networks and in services such as online games. However, unlike music and books, for which content is readily available for elec- tronic distribution, studios that distribute movies and TV shows to cable providers at high prices are often reluctant to make all of their content available to Internet-based distributors such as Netflix and Google. This is because cable TV companies are in a position to pay more for content than Internet-based distributors whose customers pay lower subscription fees. In addition, advertisers pay lower rates than those charged for TV ads. In the early days of the Internet, search engines and other sites that provide free service to consumers concentrated on attracting as many visitors as possible to their sites. Once the Internet achieved critical mass, the emphasis turned increasingly to highly profitable advertising revenue. Advertising revenue now underwrites many sites, including social networks, travel-related sites, and search sites. New display ads have integrated video and often pop up in the middle of the first page of retail and news sites. Advertisers are attempting to attract users to ads that are amusing and appealing SO that viewers will pay attention to the ads. Google now earns the lion's share of Internet advertising revenue. Its purchases of software companies including AdSense, DoubleClick, and AdMob have provided Google with the tools to manage advertising placement and creation. It n