Someone told me he thought that the fact that iTunes cannot copy Playlist Sharing files, but could only stream them, was a restriction by the server. This seemed unlikely, so I did some investigation.
Copying the MP3 in reality is painfully easy:
[pudge@bourque pudge]$ curl http://10.0.1.132:03689/databases/32/items/1104.mp3?session-id=20570 > file.mp3
% Total % Received % Xferd Average Speed Time Curr.
Dload Upload Total Current Left Speed
100 11.0M 100 11.0M 0 0 3071k 0 0:00:03 0:00:03 0:00:00 2818k
Now I have the MP3 as a file, streamed from iTunes via Playlist Sharing. Nothing on the server side prohibits this. I open it in iTunes and it is a regular ol' MP3. It has the exact same bytecount as the original file.
Note: I got the URL by peeking at the TCP/IP traffic with Interarchy:
010.000.001.104:49825->010.000.001.132:03689 (224 bytes)
So I call the exact same thing with curl, except that I save to a file instead of opening the URL in iTunes. I can't tell a way to get the URL without doing that; this is not meant to describe a way to fetch arbitrary files from iTunes Playlist Sharing, just proving that copying files the same way you stream them is technically trivial.
And more fun: if I open that URL in iTunes instead of downloading it via curl, it shows up as a regular stream in my Library. And it DOES work with get current track AppleScript, although if I play the exact same stream via Playlist Sharing, it doesn't. Again, I maintain this behavior is either a bug or intentional breakage, not a neglected feature. And because I have proven that copying the file is so technically trivial, I believe DRM concepts are most likely involved.
Jobs says that users are not being treated like criminals, but iTunes 4 assumes that if I want to share my tracks with more than three computers, if I want to copy streamed track, if I want to burn more than 10 CDs with a "protected" track, that I am doing so illegitimately. I know they need to strike a balance with their partners, but that doesn't mean I am going to just ignore these facts.
I am, frankly, more offended by the clearly false assertion by Jobs that we are not being treated like criminals than I am by the fact that I cannot share the music or burn playlists without limit (except in the case of copying files from shared playlists).
BTW, this morning my Apple ID finally was able to work with iTunes Music Store. It wasn't site traffic, nor my credit card, since I could connect with a different Apple ID at the same time, using the same credit card. I am just happy Apple fixed whatever was wrong with my Apple ID.