Music is meant to be shared. Apart from playing music life and sharing it with people that way also recordings, lyrics, melodies and so on may be shared, reused, ...
There are many ways of sharing music:
Capitalism has brought about the idea of intellectual property that substantially tries to take away the sharing aspects from music. Different, often interconnected movements emerged against this. For example the free music movement that is inspired by the successful free software movement as well as the filesharing scene (called "piracy" by the music industry) with important projects like The Pirate Bay.
→ Free music is music, where the artist explicitly supports the sharing of his music.
Recordings that get released only on a physical medium are usually "ripped" - i.e. read from the medium once to have the contents as a digital file that is more independent from a medium - and easier to copy (e.g. transmission over a digital communication networks like the internet) - and therefore easier to share.
There are several projects and communities on the internet for the sharing of (recordings of) music: