I'm hoping this will help me make some smart playlists...smarter.
Imagine I have 2 tracks tagged as A and B in their respective genre tags. I want to append X to both tags at the same time so I end up with AX and BX. Extending this idea to ~100s of tracks with a wide variety genre tags is what I want to do.
I'm still learning my way around mp3tag but haven't quite figured out how to do this yet.