Idea for free.domain.abc by drew Roberts is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
This is an idea for sites hosting music, arr, software or whatever under a combination of Free and non-Free licenses.
Consider Jamendo as an example.
currently at http://www.jamendo.com/
my suggestion is to have the current URL but as well:
so that if you go to free.jamendo.com the site will look and act the same except that all non-free content will be filtered out and if you go to nonfree.jamendo.com then all the free content will be filtered out.
Personally I only care for free.jamendo.com and can't see why anyone would want to visit nonfree.jamendo.com instead of www.jamendo.com but I include it here for completeness.
I would like to see kompoz, ccmixter, flickr, youtube and wherever function in this way as well. Kompoz possibly with some slight tweaks as it is a place for collaboratively making music together and may need a refined approach to this.
all the best,