Here, Michael Hyatt posts a helpful hint to make sure the tasks you’ve delegated via email don't fall through the cracks. In a nutshell, you BCC these items to yourself and run a mail rule to shunt your reminder into the correct folder.
Now, whenever you want to track an assignment that you are delegating via e-mail, just enter your “waitingfor” e-mail address in the BCC field. (Since most e-mail software packages sport an auto-fill feature, you can generally do this with a few keystrokes.) Now, send your e-mail. If everything is set up correctly, your e-mail will go out from your main account and you will receive back an e-mail from your new “waitingfor” account. Your email rule will automatically file it in your “Waiting For” folder.
Read full article: Working Smart: Automated Email Follow-up