And I thought it could not get any better than the iPod...
Enough cannot be said about Apple and innovation. Point in case iTunes 4. The feature list is big, but only one will truly change how people listen to music.

Forget about iTune 4's ultra simple to use, The iTunes Music Store (which for the first time makes online music purchases, ad-free, personal, and so damn easy). Forget about iTunes 4's AAC encoding (which purportedly makes smaller and more listenable music files than MP3 @ 128). Forget about iTunes portability compliance with the iPod (where's Ogg Apple? The chip supports it!)...

The real killer function of iTunes 4 is Playlist Sharing
In short, imagine wanting to hear a track on demand, but without the wait, lag, and grey-legalmatters of p2p downloading. Imagine being able ask a friend if they have a particular song, and being able to remotely connect to that friend's playlist and actually not only listen to the song in high quality but to also be able to rewind and fast forward through that track in their playlist! As much as ffwd and rwd seems like standard operating procedure in our CD players and tape decks, its never been the case in remote (streaming) MP3 usage. iTunes 4 allows for all of this and much much more.

I, for one, not only believe that this Playlist Sharing will decrease p2p usage by Mac users (which has been mediocre at best up to this point), but will also decrease illegal music trading across the OS as a whole. No need to log into Acquisition and try to find that new Bonobo single (as you wait in a queue to download it).. Ask a friend if they have it and listen to it off their machine now!

What is even more interesting is that Apple only mentions this feature on their iTunes page in one small paragraph and only mentions it in terms of sharing across the local network via Rendezvous. no mention of WAN sharing is made, but IT IS AVAILABLE! I can see the RIAA and DMCA with their puzzled looks now....