Blind carbon copy (abbreviated Bcc) allows the sender of a message to conceal the person entered in the Bcc field from the other recipients. This concept originally applied to paper correspondence and now also applies to email.[1]
In some circumstances, the typist creating a paper correspondence must ensure that multiple recipients of such a document do not see the names of other recipients. To achieve this, the typist can:
Add the names in a second step to each copy, without carbon paper; Copy Circulation
Set the ribbon not to strike the paper, which leaves names off the top copy (but may leave letter impressions on the paper).
With email, recipients of a message are specified using addresses in any of these three fields:
To: Primary recipients
Cc: Carbon copy to secondary recipients—other interested parties
Bcc: Blind carbon copy to tertiary recipients who receive the message. The primary and secondary recipients cannot see the tertiary recipients. Depending on email software, the tertiary recipients may only see their own email address in Bcc, or they may see the email addresses of all primary and secondary recipients but will not see other tertiary recipients.
Benefits
There are a number of reasons for using this feature:
Bcc is often used to prevent an accidental "Reply All" from sending a reply intended for only the originator of the message to the entire recipient list.[3] Using Bcc can prevent an email storm from happening.
To send a copy of one's correspondence to a third party (for example, a colleague) when one does not want to let the recipient know that this is being done (or when one does not want the recipient to know the third party's e-mail address, assuming the other recipient is in the To: or Cc: fields).
To send a message to multiple parties with none of them knowing the other recipients. This can be accomplished by addressing a message to oneself (or, in some email clients, leaving the To: field empty) and filling in the actual intended recipients in the Bcc: field.
To tighten the focus of an existing email correspondence. By "moving people to BCC," a sender can remove non-essential parties from the recipient list so that future reply-all's will not include them. It is customary to include a parenthetical note indicating that certain recipients have been moved to BCC. This can be done out of courtesy to uninterested parties, or as a way of politely cutting off non-essential parties from the thread going forward.
To prevent the spread of computer viruses, spam, and malware by avoiding the accumulation of block-list e-mail addresses available to all Bcc: recipients, which often occurs in the form of chain letters.
