If you couldn't upload your own music files, and thus only play tracks you've purchased, then this isn't much of a cloud "music locker" at all. It's essentially

If you couldn't upload your own music files, and thus only play tracks you've purchased, then this isn't much of a cloud "music locker" at all. It's essentially just letting you play/stream the music you own from multiple devices (where currently you can only download the music file once). Of course, that's not to say this isn't what iCloud will be, but I'd be a little disappointed if it were the case. I'd make great use of it if I could upload my own files, and probably not otherwise. Also I'd just like to toss in it wouldn't shock me if this were "US Only" at least initially.