Mass media are any number of technologies that are used to communicate to a large audience. Mass media are a form a mass communication. Radio, television, film, and recorded music are classified as broadcast media, while newspapers, magazines, and books are print media. Billboard advertisements are known as outdoor media. The Internet is the latest form of electronic mass communication. All of these are forms of mass media.
Additionally, the corporations that control the various forms of mass communication, companies like Time Warner or Comcast, are known as the mass media. With the explosion of digital communication, it has often become difficult to define whether new technologies are considered to be mass media. The Internet, for example, has websites, blogs, and podcasts, but questions arise as to whether video games constitute a form of mass media. There are many who are predicting the death of newspapers as a form of mass media because of the Internet.
The term mass media is often used synonymously for mainstream media (NBC, CNN, etc.) to distinguish it from the alternative media, although both are forms of mass communication, simply reaching different sized audiences. Mass media can be used for more than news and advertising. Public service announcements and emergency broadcast warnings are two of the more public-service uses of mass media to bring an important message to the public's attention.