I'm not sure where the data is coming from, as I don't think eMusic has an API, but this morning I came across a listing of all albums recently added to eMusic. eMusic is notoriously bad at cataloging records, especially anything close to what you'd consider ambient, so sorting by genre isn't particularly useful. But you can sort by "Label" and "Artist", and while I don't know that I'd use this thing too terribly often for finding new tracks, it's a nice thing to have.
Speaking of finding stuff on eMusic, boy are there so many things they could do to improve the way the site works. If anyone from is eMusic reading this, maybe you'd like to have an ambient-music-listening, MLS-having, information & user experience professional on hand?