nice music library is Youtube and maybe even Soundcloud. One can create playlist and play favorite music. BUT these are not P2P (user to user sharing), these rely on central server.

There is another interesting project that allows uncensored access to the media library of all its users & playback of the files & creating playlist.

It is Zeronet website called ZeroLSTN. (you need to install & run Zeronet and then open this URL once ZeroNet started - opened its page in your web browser)

The beauty of the ZeroLSTN is that the music you listen/download you start sharing with others.

It works via torrent in the background.

No need to register, user can share his/her whole music library (folder+subfolders) and if he has his computer online, others will be able to download/play his files, meaning if someone download an audio file, one can turn off computer and the file is kept online by other seeder/s.

This is fully distributed media library (P2P), maybe the best P2P music library out there.