An iTunes Thing That Would Be Cool

If, after rating songs, I could "trade in" the stuff I rate at 2 stars or 1 star for other songs... like get "store credit" for stuff I don't like.

This would be great feedback for publishers and artists, because they'd know what I don't like. And it's a win for me because it means I can try out more music and "keep" the songs I like in my library. I don't need any money back, I'd just like to license different content and find music I enjoy!