Incorporating dynamic behavior in SMTP

The all-pervasive and ubiquitous email is essentially static in nature. An email once sent remains as such and the sender no longer has any control over it. There is no mechanism available for changing any portion of the email that is obsolete: instead a new email has to be sent, thus cluttering the receiver's mailbox. In this paper, the authors have proposed an extension to SMTP that would let the sender of an email safely replace and in some cases, remove emails sent by him. The underlying motivation and a concise, yet reasonably comprehensive implementation mechanism has been described here.