I completely agree!

Yes! Needed

I agree...my memory is not as it was and it would be helpful to look back to see what you had said to a person....perhaps I just talk too much to too many people

I have already done that...but not added it as I have to ensure that spam messages, that are NOT delivered
still appear as if they had delivered...otherwise spammers find a way around the anti-spam mechanism

I know you've said it exists, and that's great - but even a little arrow or something that appears next to a message in your inbox once you've replied to it would be handy. I lose track sometimes and then don't bother replying cause I think I've already sent one.

Thats a great idea Toby, wtg. that way if we do have a problem with someone you can see what we have written as well, if need be.