Short voice greetings

WAV, AIFF, QuickTime (via regular HTTP server), MP3

Narration (news broadcasts, interviews, and other voice-only content)

Streaming solutions such as RealAudio, Windows Media, or QuickTime for large audiences; RealAudio or QuickTime via HTTP server for limited traffic and few simultaneous listeners

Background music (ambient sound loops)

MIDI, Beatnik, WAV

Short interactive sound effects (such as button rollover and transition sounds)

Flash, Shockwave, Beatnik

Music samples for a limited audience

MP3, RealMedia, or QuickTime via HTTP server

Music samples for a large-scale site with heavy traffic

Complete streaming solution, such as RealSystem or Windows Streaming Media

Radio-style music broadcasting

RealMedia System, streaming MP3s (via a streaming server such as SHOUTcast), Windows Media System

Distribution and sale of CD-quality audio

MP3, Liquid Audio

Live broadcasting

RealMedia System, QuickTime, Windows Media System

Musical e-greeting card

Flash, Beatnik, MIDI or WAV background sound

Specialized audio applications (such as virtual CD players, mixers, etc.)

Flash, Shockwave, Beatnik, QuickTime