Radio broadcasting in the United States is a major mass medium. Unlike radio in most other countries, American radio has historically relied primarily on commercial advertising sponsorship on for-profit stations. There is a smaller not-for-profit "public" sector, funded chiefly by listeners. Shortwave broadcasting in the United States includes federal government programs for overseas audiences. Radio broadcasting became popular in the 1920s, alongside the new film industry. The arrival of television in the 1950s forced radio into a niche role, as leading participants moved into the much larger field of television. In the 21st century, radio has been adjusting to the arrival of the Internet and Internet radio.