Pandora Radio is an automated music recommendation service and custodian of the Music Genome Project. Users enter a song or artist that they enjoy, and the service responds by playing selections that are musically similar. Users provide feedback on approval or disapproval of individual songs, which Pandora takes into account for future selections.

While listening, users are offered the ability to buy the songs or albums at various online retailers. Over 400 different musical attributes are considered when selecting the next song. These 400 attributes are combined into larger groups called focus traits. There are 2,000 focus traits. Examples of these are rhythm syncopation, key tonality, vocal harmonies, and displayed instrumental proficiency.

A station is set by specifying an artist or song, or a combination of multiple items of any kind in a single station. Listeners can tune into pre-made genre stations and other users’ stations. Each track played can be responded to with favorable (thumbs up) or unfavorable (thumbs down) buttons, which determine if it should be played, and how much should similarly classified songs be played in the station. A second negative response to the same artist will ban that artist from the selected station unless the user has marked the artist positively on another occasion. No response is applicable to musical attributes or to albums. An unfavorable response immediately stops play of the track.

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