Nested URLs are useful to signify partonomy. If you delete an artist, you would expect his or her albums to be deleted as well. Versus, if you delete an album,

Nested URLs are useful to signify partonomy. If you delete an artist, you would expect his or her albums to be deleted as well. Versus, if you delete an album, you wouldn't expect the artist to be deleted. And for completely unrelated things (which both would sit at the top level), again you wouldn't expect a cascading delete either.