I was used to listen to music on my computer on a player called Spotify last year, but the company decided to make it private, so you should bougth a premium account and pay of course or you just can hear few hours per week.
At that time I decided to change of music player, I searched over the Internet to find a good one and I found one, Grooveshark
I think most people that weren't wandering to pay did the same, they just get another music player, so Spotify lost quite a bit of clients.
Now I realized that Grooveshark is better even thougth it's free, so I think that this company will be important in a close future. In my opinion, these companies are a good way to earn money, because each one has his own comercials and people get a big benefit of those computer music players.