Sometimes mail conversations get out of hand. If you're in the CC field and folks keep hitting reply-all you'll keep getting all the e-mails. Now suppose you've lost interest in this mail conversation and any follow-ups (perhaps it turned into a "favorite christmas song mailthread"): how can you slip out of this thread?
The only thing I could think of was ask a colleague that's also in the thread to "sacrifice" him/herself by hitting reply-all and removing your address from the CC field. That's not really a solution though, because it's not something you can do yourself.
PS. In my specific situation we all have inboxes on the same Exchange server (and my client is MS Outlook 2010) - but preferably an answer would also work if non-exchange mailboxes are involved.