It's taken a month or two for this to bubble into public consciousness, but iTunes 4.7.1 has a nasty limit on its music sharing. Previous versions of iTunes 4 limited you to five simultaneous connections to a shared library, but this has now been changed to five "different users" a day:
I'm not the first person to discover this (that may well be the author of this forum post, although Neil Crosby's writeup was the first I saw). However, it does affect me more than most, because I strongly suspect the behaviour change is entirely to try and get around the use of shared library copying applications like OurTunes and my own Blue Coconut.
Blue Coconut certainly, and the other looks probably, generate a new connection to the iTunes share. If you're copying from one machine, that used to mean that, while you were doing so, they could only share to four "real" users, but I never really felt the need to spell this out.
Additionally, OurTunes tries to connect to any share it can see. Run five copies in a big enough university network, and you've just closed down iTunes sharing for everyone.
Of course there are ways around this. You can run your own DAAP server (a topic that I'm intending to write about in more depth, but for now your magic keywords are mt-daapd, Music Publisher and accessTunes), but for most users that's not going to mean anything. On the other hand, except for colleges, I wonder how often this is a problem.
Copying from iTunes shares is also, of course, not something Apple wants to be associated with. It's surprising they changed this rather than the DAAP authentication. Mind you, oddly, this restriction will be much harder to work around than a MD5 change.
I started drafting this yesterday, and in the meantime Cory Doctorow has waded in with another of his "all DRM is bad! Apple are evil! Don't trust them!" rants. I question a lot about this, but I'll confine myself to one obvious point. I didn't pay for anything to do with iTunes. It's free, it's running on an OS that came for free with my computer, and it shares (I don't like the word streaming: another rant) songs that I didn't pay to have on my computer. Apple may be removing a feature, but it's a feature that nobody else is even close to implementing. Sure, it kind of sucks, but no more than that.