It is very nice to have a third mailbox, but those users always ask for more... What would be of even greater help for me is a fourth mailbox where all non-personal messages would automatically go (notification of finished games, tournaments, etc.). It is a very repetitive task for me to delete all of them in order to keep only personal messages in my inbox.
(Especially annoying when playing match backgammon, where every single game generates a message)