Online radio is a newer phenomenon relative to standard radio band frequencies. Online radio does not broadcast to standard radios but can be listened through various programs including, but not limited to, Winamp, RealPlayer, and Windows Media Player. Accessing these streams of automated or DJed music can be done through websites that post listings, such as shoutcast.com, Radio@aol, or through host companies which offer their own browser installed programs to listen, such as Live365.
Broadcasting Internet radio is generally done through two major programs: ShoutCast and Winamp. ShoutCast comes in both server and plug-in forms. The server is where the music is actually broadcasted to the Internet from whereas the plug-in works with Winamp to send out the stream (sound) to the ShoutCast server. Using various sound formats (i.e. .wav, .mp3, etc.) and linerecs, line recordings in which the user can broadcast sound live from sound card and/or microphones.
Online radio stations vary immensely in format, listener audience, and purpose. Formats generally fall into genres as prescribed by Shoutcast. These formats include: alternative, classical, comedy, country, dance/house, funk, jazz, metal, mixed, pop, rap, RnB, rock, talk, techno, the 80s, the 70s, and world. Listener audiences vary from the obvious zero (new stations, poor formats, and/or quality) to nearing 3000 listeners via ShoutCast or more via Live365. Finally the purpose of stations is almost the most intriguing. Many stations broadcast solely for listeners. Some, however, use online games (i.e. The Sims Online, Everquest, etc.) or other settings of common interest to serve the listeners with music, information, and events.
Overall online radio stations are quite enjoyable. They allow listeners to break free, barring bandwidth restrictions, of common commercialized radio and enjoy listener supported, more liberated radio. There is, be forewarned, quite a bit of excrement broadcasted and claimed to be valuable (though who is any writer to pass judgment). Regardless, there is a lot to take in that is both unique and valuable.
A sampling of online radio can be found at the above listed sites or, for a more personal experience, try http://www.radioalphaville.net