See that! Even fred_gnuf has a good idea once in a while.
I heartily endorse fung's suggestion. On those rare occasions when someone posts to me, I'm always concerned that I'm going to reset my unread post count for the board the message was posted on. So, instead of clicking on the link in my mailbox, I plod slowly through the unread posts for the boards I have marked. If the light still hasn't gone out (my message count is unchanged), I click on the mailbox link.
Someone may (or may not) have once told me that clicking links in the mailbox doesn't reset the unread post count, but ...
a) I'm not sure of that
b) I'm afraid the message might be interesting and I'll have to do some NEXT's to see what followed ... which will, I fear, reset the unread post count.
Ah, fung, your brilliance is astounding.
Fred