[Edited Message Follows] It's not a new feature, but a very old one, and it is very annoying. That being said, those who have an e-mail service that allows this feature to be activated do have far better protection against spam, spoofing, etc., than those that don't. Your reply to that message is used to whitelist your own e-mail address by the recipient's e-mail filtering software and is only done the first time you attempt to contact them.
If you do not reply to it, in most cases your e-mail address will remain blacklisted by the recipient's e-mail filtering software and any subsequent messages you might send are either immediately classed as spam or trash. So, if this comes from someone with whom you do wish to correspond, it is best to make that one extra reply so that your original message, as well as any subsequent messages, go through. Brian
