end-user should be able to create TAGS for songs. include standard tags like "rock" and "soul", but allow the user to create their own tags, and use this as cross-referenced information to organize not only the user's own music collection, but also to match characteristics of other users' music or playlists. user-created tags would allow Spotify to recommend more musically accurate songs, as the characteristics and style of the songs have been peer-reviewed. it's no secret that Spotify radio is weak. Utilize the social network of Spotify by tapping into the users' knowledge and experience of music.
I think there should be a finer way to create a radio station you really like. You should be able to rate songs, artists, albums and genres on a finer scale, and then all the ratings would be considered for your personal radio station... The higher a song would be rated, the more often it would play, and broader ratings would carry over into the probability of songs playing, maybe skewed by the other recommendation factors now in place... So that the average assumed rating for otherwise unrated songs in an album, for instance would correspond to the rating of that album, but the individual songs still would play more or less often depending on how popular they generally are and all the other recommendation factors now in place.
There used to be a radio service called Launchcast some years ago which offered that level of customization (they used a rating scale of 0 to 100 for each item), but sadly they stopped broadcasting some years ago.
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