Just for fun:
Just imagine you have two girl friends. Forwarding some interesting mail to both. If anyone notice the To address, then you will end up in hospital.
If you like to hide email address from other recipients while sending to multiple recipients, this article will explain how to do. I believe this will helpful for organization and those who concerned about Security.
How to do?
It is very simple.
Whenever you send mail to group of mails, fill the mail address in BCC field instead of To field (leave the To field empty).
BCC is expanded as Blind Carbon Copy.
The receiver will see sender and his address.
He can’t see others address.