yeah and what excellence said, fileshare, filestube and such. And indeed, lots of crappy diy ones aswell and youll find them among the good ones. Some blogs ive seen add a diy. Big plus there.
Legit PAID record pools are the best source for what you hear today. New artist don't do the acapellas or instrumentals as much as they did back in the day. I think sales and potential hits are the reason. Producers and artist try to hang on and ride the first release as long as possible. When the song dies down they'll release instrumentals and acapellas for remixes.