Just a probably obvious note: there's a difference between streaming and progressive streaming (sometimes called progressive download). One maintains a constant stream across network bandwidth changes (through bitrate adjustments) and one maintains a constant bitrate across stream changes (often through buffering). Hulu, Netflix, YouTube, etc. often uses a combination, but the relationship between the two can be used to get to a target even faster than you technically could with just bandwidth. If general quality expectations rise quicker than buffering irritations for instance. Not that any of this has to do with pure music file downloads now. That said increasingly files with wrappers and codecs with metadata at the start of the file can be decoded on the fly. So would people care if an album took hours to download if they could listen to it during? May be some synergistic progress along with bandwidth increases coming.