mass media, modes (or, less commonly, a single mode) of mass communication whereby information, opinion, advocacy, propaganda, advertising, artwork, entertainment, and other forms of expression are conveyed to a very large audience. In this, the most general, sense of the term, mass media have included print, radio, television, film, video, audio recording, and the Internet—in particular, the World Wide Web and Internet-based social media. The term mass media is also used to refer collectively to types of public or private organizations that produce or disseminate particular forms of expression through such modes, including newspapers and wire services, periodicals, book publishers, libraries, radio and television networks, movie studios, and record companies. Notably, since the late 20th century the Internet as a mode of mass communication has come to provide alternative platforms for mass media organizations that were once restricted to earlier-established technologies. It is now common, for example, for newspapers, periodicals, and books to be published on the Web or through Web-based applications (indeed, some publishing companies have abandoned the print medium altogether) and for musical recordings, television programs, and films to be accessible on individual websites or through dedicated streaming services. Finally, in the United States another common referent of mass media is the group of mostly private corporations that publish or broadcast news and news commentary for a nationwide audience. Mass media in that sense have often been criticized, collectively and individually, for alleged liberal or conservative bias in their reporting on important political, economic, and social issues.