Internet radio (also known as web radio, net radio, streaming radio and e-radio) is an audio broadcasting service transmitted via the Internet. Broadcasting on the Internet is usually referred to as webcasting since it is not transmitted broadly through wireless means. Internet radio involves a streaming medium that presents listeners with a continuous "stream" of audio over which they have no control, much like traditional broadcast media; in this respect, it is distinct from "on-demand" file serving. Internet radio is also distinct from podcasting, which involves downloading rather than streaming. Many Internet radio "stations" are associated with a corresponding traditional (or "terrestrial") radio station or radio network. Internet-only radio stations are independent of such associations.

Internet radio services are usually accessible from anywhere in the world—for example, one could listen to an Australian station from Europe or America. Some major networks like Clear Channel in the US and Chrysalis in the UK restrict listening to in country because of music licensing and advertising concerns.Fact: date=June 2008 Internet radio remains popular among expatriates and listeners with interests that are often not adequately served by local radio stations (such as progressive rock, ambient music, folk music, classical music, and stand-up comedy). Internet radio services offer news, sports, talk, and various genres of music—every format that is available on traditional radio stations.

Streaming

The most common way to distribute Internet radio is via streaming technology using a lossy audio codec. Popular streaming audio formats include MP3, Ogg Vorbis, Windows Media Audio, RealAudio and HE-AAC (sometimes called aacPlus). The bits are "streamed" (transported) over the network in TCP or UDP packets, then reassembled and played within seconds. (The delay is referred to as lag time.)

Early history

In 1993, Carl Malamud launched Internet Talk Radio which was the "first computer-radio talk show, each week interviewing a computer expert." This was Internet radio only insofar as it was conceptually a radio show on the Internet. As late as 1995, Internet Talk Radio was not available via multicast streaming; it was distributed "as audio files that computer users fetch one by one." However Malamud was among the foremost proponents of multicasting technology. In late 1994, his Internet Multicasting Service was set to launch RTFM, a multicast Internet radio news station. In January 1995, RTFM's news programming was expanded to include "live audio feeds from the House and Senate floors."

A November 1994 Rolling Stones concert was the "first major cyberspace multicast concert." Mick Jagger opened the concert by saying, "I wanna say a special welcome to everyone that's, uh, climbed into the Internet tonight and, uh, has got into the M-bone. And I hope it doesn't all collapse."