so the iTunes store is now moving toward all drm-free music, but "drm-free" doesn't mean it's free of other copyright control measures...

the name and e-mail address from your iTunes account are stored in every song file. if you open up an "iTunes plus" .m4a file in a text editor, your should see your name near the top, and if you do a search you can find your e-mail address.

i'm guessing someone out there has already written a program to strip that data out.

(although i use the iTunes store occasionally, my online music dollars go mostly to eMusic.)