Not when the original message in the thread was sent or received. If I sent a message to you on June 15th of 2009, but you sent me an email yesterday that I have dutifully archived with a label, then when I go into that label space I have to remember that I sent the email back in June.
For me, it's easier to go into a label, instead of hoping that search terms I may use will bring up that important message.
Thoughts?
