Hurrah! Magnatune is mostly back to working now.
Here is a complete list of the things that I know are not working, which isn't very long:
1) podcasts are not available, and are not currently being built
2) audio streams for Second Life are not currently available
3) shoutcast radio stations (i.e., listening from iTunes radio) is not working.
While I do want to get these things working, they're all lower priority for me.
IMPORTANT: If you find something that isn't working, that isn't on this list, please DO post a comment here and I'll get to it right away. If you put your email address in the comment (it isn't posted publicly) I'll let you know via email when it's fixed.
No data was lost because of the problems or downtime.
Thanks for your patience!