Bcc – How to use Blind Carbon Copy and why

Sean McNamara
22 September, 2007
View more articles fromthe author

A mistake that many people make with e-mail (and not just newbies) is when they want to e-mail a lot of people (usually with jokes, recipes or chain letters), they put all the addresses in the To: or Cc: fields. Most people would think that’s quite alright, but there are several problems with this:

Not everyone you know would want their e-mail addresses broadcast to people they don’t know.

Some malware (malicious software, such as worms, viruses and spyware) programs scan the e-mails on PCs to garner e-mail addresses for further dissemination of their noxious loads.

Recipients may need to scroll down a long list (depending on their e-mail client) to get to the meat of your message.

Less of an issue these days, but if you have a lot of e-mail addresses in the message headers, they may equal the total size of the rest of the message, wasting bandwidth.

Luckily, there is a solution that’s been around for a very long time — the Bcc: (Blind Carbon Copy) field.

Most people are are aware of the Cc: (Carbon Copy) field on e-mail clients (named after the paper copies made with carbon paper ).

When indicated on a typed page, the Cc: field would show who received copies of the document, but not the original (usually for the purposes of informing the extra recipients of the original communication).

It was always possible to make more carbon copies than noted in typed documents for distribution to recipients the noted recipients didn’t know about. This is where the idea of Blind Carbon Copy comes from — it’s “blind” in the sense that the recipients don’t know everyone who has received the document (see “Hot links”).

Bcc: has been available in e-mail clients for as long as the To: and Cc: fields have been, but it’s not used nearly so much. When you use the Bcc: field, the Bcc: recipients each receive a copy of the e-mail, but the Bcc: field is not relayed to anyone, so those addresses are not available to the recipients nor to any malware on their computers.

Using it.

Here’s how to enable and use Bcc: in the most common Mac e-mail clients.

By default the Bcc: field is hidden — you can show it by opening a new message, then selecting “Bcc Address Field” from the View menu A. The Bcc: field is then shown in the message composition window B. It will continue to be shown in new message windows until you deselect it in the View menu.

Entourage (v.X and 2004).

The Bcc: field is enabled and shown by default in Entourage. When you start a new message, the Bcc: field is displayed C.


Eudora has the Bcc: field available by default D.


Both Thunderbird and Netscape have the Bcc: field available by default — you use the popup menu to change the type of field from a To: or Cc: E.
Some more notes about the Bcc field and why/when to use it can be found at the United States Computer Emergency Readiness Team (US-CERT) web site.

Leave a Comment

Please keep your comments friendly on the topic.

Contact us