"I encode a lot of music to OGG, I did not realise I was one of only 12! ITMS does not support MP3 either, I wonder how many MP3 users there are looking from within the RDF? 25? 50?"
Dude, it's context. You stated the above. The context is "encode". So, the response was about encoding your music. If you want to encode your music in mp3 then it's a non-issue.
And, further, if they are "MP3 users", presumably they are because they have been encoding their music in mp3 and have no problems using iTunes. If they want to buy from the ITMS, then their AAC files will still have no problems with iTunes. The only problem is the one you have, the fact that you can't read your own post and realize the context you put your comments in, led to the confusion.
Milking iTunes for Every Penny