Blind Carbon Copy. For anyone who has ever sent e-mail, the BCC field is the one you use when you don’t want the main e-mail recipient to know that the same message is being delivered to one or more people other than the main recipient himself (or herself!). It is also a good practice, or netiquette as its known, to use BCC when you are sending a message to multiple people. By using BCC you will be prevent one recipient from knowing the e-mail id of another recipient. This helps reduce the likelihood of any of the recipients trying to use the e-mail IDs in the mail for spamming.