The NAS operates directly through a WAN. Once set up, you can access the device wirelessly and direct your apps through that. Basically a standalone storage unit which acts as your personal cloud.
You can connect wirelessly to your music database, which can stream to your mobile, you can backup, sync and even arrange a torrent to save directly onto the Synology device. This will revolutionize the NAS industry and is certainly very useful. Check out Synolgy for more.