Ive never used such of that stuff... i prefer the good old magazines, made out of paper, or internet magazines where i can read about stuff whats new in the szene. atfer being interested i look at the pages of the bands or looking for a youtube channel and if it still sounds good for me, ill buy stuff of the band.
I dont see bad stuff with pages like soundcloud, bandcamp etc.
A long time i was in a death metal band, but its some years ago and if that kind of sharing music would have exist in those days, we would be happy to have it. but even now i dont think that bands should have problems with marketing and getting to people who could like them.
All in all i think that its some good stuff for music what is happening now with stuff like bandcamp, soundcloud, noisetrade and and and. And no one has to do it, so no one should cry about it, if it sucks for him/her.