+1 I always space on grabbing the auctions I bought the night before from my butler, I think it should just tell you everything that happened whiel you were gone like this: "You have X new messages, X packages, and X people have visited your street." Or maybe even have it be different based on situations, like if you just have a message it would say "X says X" Etc.
But really, it should be sufficient to associate the "hi there" animation to something new in the mailbox (if the butler waves his hand, then you know there's something to read)