There are several types of mass media in the United States: television, radio, cinema, newspapers, magazines, and websites. The U.S. also has a strong music industry. New York City, Manhattan in particular, and to a lesser extent Los Angeles, are considered the epicenters of American media. Theories to explain the success of such companies include reliance on certain policies of the American federal government or a tendency to natural monopolies in the industry, with a corporate media bias.
Many media entities are controlled by large for-profit corporations who reap revenue from advertising, subscriptions, and sale of copyrighted material. American media conglomerates tend to be leading global players, generating large revenues as well as large opposition in many parts of the world. With the passage of the Telecommunications Act of 1996, further deregulation and convergence are under way, leading to mega-mergers, further concentration of media ownership, and the emergence of multinational media conglomerates. These mergers enable tighter control of information. By the early decades of the 21st century, a handful of corporations control the vast majority of both digital and legacy media. Critics allege that localism, local news, and other content at the community level, media spending and coverage of news, and diversity of ownership and views have suffered as a result of these processes of media concentration.