Here is a site where you can check music to see if it is supported by the RIAA. They are not interested in those they don't support so if you share music, you should make sure you search in this site to see what music the RIAA is interested in.

Needless to say, they are not happy over this site.

here (http://www.magnetbox.com/riaa)

Excellent work Wet1 but alas all the music i want is RIAA supported.