Follow both sides of a threaded discussion in Mail

Cats: News|

Mail's View » Organize by Thread option is a great way of seeing one side of an email conversation. Until recently, however, I didn't realize that I could see both sides of that discussion. By selecting multiple mailboxes in the left panel (as described in this hint), Organize by thread will interleave all messages in all selected mailboxes.

So, for instance, with both Inbox and Sent selected, I can see the organized messages from both sources. If I add Drafts to the selection, I can see what I wanted to say in the its full context. It's a great way of seeing both sides of a long-running discussion in Mail.