ELDA - a Microsoft Outlook 2007 add-in that alerts users of e-mail sent to them that has been delayed or lost

I'm not entirely sure how this Outlook 2007 plug-in works, but this Microsoft Research project seems to have the ability to alert you of delayed or lost e-mail that you have sent. I am still trying to figure out how it works, but so far it seems like a pretty cool, and free, add-on for Outlook.

Give it a try here.