If a member replies to a older note, you will receive an email like http://www.sitename.com/note/show/12703#last which will take you to the message.
However if you just click on your inbox, the message is not moved to the top. So if you miss the email, it is very difficult to know that you ever received a new message.
updated by @dazed: 04/19/14 05:17:44AM
JAMROOM
