Tape trading is an unofficial method of distribution of musical or video content through the postal system, which was prominent in the 1980s and 1990s. Although most commonly used to distribute and publicize limited-release musical demo tapes in underground musical genres such as punk, hardcore, and extreme metal, the system has also been used to distribute bootleg recordings of live concerts, recordings of radio broadcasts, original radio-style programming by amateur broadcasters, and videotapes of underground films and pornography.