One thing that I think could really make Spotify better is a way to add notes or a user description of sorts to songs once they're added to a playlist. For example, I created a playlist called Trailer Tracks that has a number of songs featured in popular movie trailers. However, there is no way for me to tag each song with the trailer it was featured in.
A way of doing this, or allowing the admin of the playlist to add a description of why a certain song was added or what it means to them could really add a new twist on Spotify and take music sharing to a whole new level.
There is just too much good music these days not to have a solid playlist for any mood or occassion. I wish I could just add tags to songs I like in Spotify, then when I'm in need of a good playlist I can just search for and filter songs based on my own tags to quickly create a playlist without having to sit and sift through all of my music to drag and drop specific songs into the playlist. Tags could also be implemented as a powerful music discovery tool if you could choose to search tags of friends or even the entire Spotify community, or just view tags given to a particular song by other users.
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.
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