I have looked into sites like SoundCloud and BandCamp and they do have very interesting qualities. SoundCloud and BandCamp both allow for you to upload your own music with your own cover photo and all. Very professional idea, the only thing is everyone can upload their own music. Leading to a larger competition of artists in one place which is harder to market. It does make sharing your music very easy as you have it saved in a safe place where the public can make a listen. Personally I would record a full album before beginning to post singles on sites like BandCamp and SoundCloud.