Internet SMTP-based e-mail systems do not guarantee delivery of messages, much less timely delivery. Using these systems, e-mail can sometimes be delayed by hours or days, or even lost without notification. E-mail loss, even if infrequent, is costly in terms of missed opportunities, productivity losses, and unfortunate misunderstandings. A detailed Microsoft Research study performed over several months found that using such systems, e-mail loss rates can be as high as 3.36%.


Undelivered or Delayed e-mail Notification System augments existing SMTP-based e-mail infrastructures with a notification system that alerts recipients of undelivered or delayed e-mail. The alert consists of a short, fixed-format fingerprint of the delayed or undelivered e-mail, which preserves sender and recipient privacy and prevents spoofing by spammers. In addition, Undelivered or Delayed e-mail Notification System doesn?t disrupt the existing SMTP system, preserves the asynchronous nature of e-mail, and does not affect existing defenses against spam and viruses. And, because Undelivered or Delayed e-mail Notification System does not require a PKI for e-mail users, it does not affect someone?s ability to repudiate an e-mail. Finally, it places minimal demands on users by automating generation, retrieval, and verification of alerts.

Software, called ELDA (E-mail Loss Detection Add-in) that implements Undelivered or Delayed e-mail Notification System for Microsoft Outlook 2007
Research papers, presentations and other documents that describe the technology