Updated this March (distressingly recently, thus not ignorable), it says that iTunes Match network problems might be because of problem connecting me to a long list of addresses. Of that last, _3_ of them have 100% packet loss when I try to ping them (the rest are Golden).
Here's the advice: "If the issue disappears while connected to another network, you may need to work with your support options to open access to" list of addresses. Well, I couldn't do a comparison to a successful network connection, but this sure seems bad.
ETA: Oooh, Down for Everyone says it is NOT JUST ME! Woot! I can Wait and it will Magically Get Better. Eventually.
DAMNIT: albert.apple.com is down for everyone; gs.apple.com and mzstatic.com is just me. *grrr*
ETA still more: I'm no longer convinced that this was the problem, however I did blow away my NetworkInterfaces.plist file and restart. One of the effects of that (or one of the other things I did -- there are reasons I was a developer and not in IT. I'm just not disciplined enough) was that it sort of blew everything out of the cloud for me and restarted. Gaah. OTOH, everything eventually went back up and looked good. *phew* But it's still crazy slow updating, so I don't know what's going on. I'm going to not worry about it for a few weeks and just finish the ripping to the hard drive part of the project. The match stuff can be done later, if it keeps dying now.