Gee, I figured that process out more than a year before Apple originally created that document. If you have a real understanding of the operations of a multi-user OS, it becomes obvious that for multiple users to share a music library, it has to be stored outside of a specific user's protected space.

What's still missing is the ability to fully share one library among all the machines on a local network. The existing iTunes Sharing feature is a step towards that, but it suffers from what I consider to be two major limitations/drawbacks: iTunes has to actually be running and sharing on the machine where the music is stored, and no tag information can be modified from the guest machine (which is primarily of significance for ratings and play counts).

The first limitation means that in order for me to listen to my music from my iBook, I have to be logged in on the desktop machine and iTunes has to be running; there is no way to access that music through iTunes Sharing if no one is logged in on the host machine. (And iTunes distinctly does not like having its Music Library located on a remote volume--I've tried.)

The second limitation interferes with my preferred listening habits. Approximately half of my library is still unrated (because those files were all ripped long before iTunes supported ratings), so I try to spend some time each day listening to the unrated tracks to assign them ratings. Since I can't set ratings from the guest machine, I have to spend that time actually at the desktop machine, which often will interfere with other tasks I'm trying to do (tasks which are one of the reasons I bought the iBook in the first place). And play counts are not updated for shared listening, so Smart Playlists I have that are based on play counts won't know that I listened to those tracks.

I suppose Timbuktu would be a solution to the second problem, but it's far too pricey to purchase just for that. There isn't really any security or piracy problem inherent in allowing the owner of the shared files to choose to allow the play counts to update for files played by guest users, except what is already inherent to the concept of the sharing itself. In my case, since I don't have the iTunes Sharing port forwarded by my router, no one not in my household is going to be listening to my music anyway (and, if I were running iTunes 4.1 or later, the program itself would disallow that), so for play count purposes, my listening remotely is just as valid as listening locally.

As for the first problem, even Timbuktu wouldn't fully solve that, because you still have to log in to launch iTunes, even if you're logging in remotely via Timbuktu. I ought to be able to launch iTunes for sharing purposes only as a background process not tied to a specific user.