This study reviews the history of television audience fragmentation in the United States and uses a secondary analysis of Nielsen peoplemeter data to assess the current state of both fragmentation and audience polarization across 62 of the most prominent television networks. Audience fragmentation is more advanced than is generally recognized. Polarization, the tendency of channel audiences to be composed of devotees and nonviewers, is also evident, though modest. Contrary to the "law of double jeopardy," there are now many examples of both small-but-loyal and small-but-disloyal audiences. Loyalty and audience fragmentation affect network profitability and have social consequences.As recently as 1977, three broadcast networks accounted for over 90% of all the prime-time television watched by Americans (Veronis, 1994). Everyone consumed a similar, broadly appealing, diet of news and entertainment. Since then, an avalanche of programming, much of it targeted to specific segments of the population, has fragmented the audience almost beyond recognition. These changes affect network profitability, but they can have social consequences as well. Theorists have raised two related concerns. One is the fear that nations will be denied a powerful medium of social integration in which all citizens can attend to the nation's business (Katz, 1996). Another even more worrisome prospect is that technology and advertiser-driven programming will reconfigure the mass audience into many small, relatively exclusive communities of interest that never encounter dissident voices or different points of view (e.g., Sunstein, 2001;Turow, 1997). These concerns map onto two features of audience behavior: fragmenta-James G.