basically iTunes match sounds like a neat way to upgrade your audio files from lousy 128kbps joint stero to 256k AAC stero files in Apple’s iTunes quality.

there is a catch, however. Your files will be tagged by Apple with your name and your appleID – obviously to prevent you from later sharing them with someone else but who knows for what else…
first I thought it’s only in the database as suggested in other posts but they quickly found out it is embedded in the file.

Not that I care as I don’t intend to share my music but it would have been nice to be informed that all music files will be tagged with my user ID now… or probably I was told.. in that 52 page EULA that everyone reads.. right? RIGHT? ;)

See here in iTunes:

using hex exit: