Peter Kafka notes that Apple isn’t referring to the new ability to listen to all your music on iTunes before you fully download it as “streaming”. Okay, then if this isn’t music streaming, then neither is Google Music Beta on Android. Because I have from an excellent source that it does the exact same thing.
But why do it this way and not 100% streaming? Two reasons:
1) Performance. Without caching the music, if you lose a connection, it’s game over. Music stops. That’s why all of these services cache and/or buffer to some extent, including things like Pandora.
2) Legality. You can argue semantics, but if you hit a button and a song instantly starts playing before it’s fully downloaded to your machine, that’s streaming. But if these guys call it that, that means another deal is likely required with the music labels. So instead it’s not called “streaming”, it’s called “downloading on the fly” or the like.
Update: And here’s a video showing that iOS will delete the cache after a song is done playing. Call it what you want, that’s streaming — the right way to do streaming for connection interruptions. The music does not permanently reside on your device, nor does it need to fully be there to start playing.