15th June, 2006
I just discovered a nice feature in Mail: If you click the status icon indicating that a message has been replied to, the reply opens up in a new window.
The icon resembles the "snap back" icon found in both Safari and iTunes. I guess those icons always have an action.
Speaking of replies, making a smart mailbox matching either "Message is in Mailbox Inbox" or "Message is in Mailbox Sent" and then turn on "Organize by Thread" in the View menu, it becomes very easy to follow a long correspondence.