A netlabel (also online label, web label or MP3 label) is a record label that distributes its music primarily through digital audio formats (mainly MP3 or Ogg Vorbis) over the Internet. These music-files are often called netaudio. While similar to traditional record labels in many respects, netlabels typically emphasize free distribution online, often under licenses that encourage works to be shared (e.g., Creative Commons licenses), and artists usually retain copyright. Most employ guerrilla marketing to promote their work; few netlabels earn money for participants.