Should have done it six months ago.
If you use Gmail or Google Apps, add the Boomerang App or extension to your Chrome browser for added functionality with your email account.
1) Send an email to limbo after specifying when you want it to return.
2) Get a SEND LATER button for scheduling when to send an email.
3) Get an alert if you don’t get a reply to your email.
4) Get Read receipts.