It actually is a blessing... and very clever, too. You can auto-whitelist addresses you send email to, and for those "do not reply" type messages you can use keyword or time-sensitive email addresses that are modifications of your normal email address.Sounds like more of a hassle than a blessing. From what that says, unless they're in a whitelist, they have to respond to an e-mail. What happens with those e-mails that will sometimes get sent through from services that always say &Do not reply to this message...&? And really, who's going to want to force everyone that e-mails them to send a reply back so their e-mail comes through? It's a neat idea, I just don't see it as a viable one to make anyone use.