What is the “BCC” field?

BCC stands for Blind Carbon Copy. It's a way to send someone a copy of an email without other recipients knowing about it. When you put an address in the BCC field, the person receives the email, but their address doesn't appear in the message that everyone else sees.

Here's how it works: when you hit send, your mail server reads the BCC field and delivers the email to those addresses. But before the message actually goes out to anyone, the server strips the BCC header completely. It's gone. That's why no one else can see who was BCC'd, it never makes it into the delivered email.

BCC is different from CC (Carbon Copy), where everyone can see who else got the email. With CC, you're saying "these people should know about this conversation." With BCC, you're saying "this person should see this, but no one needs to know they're seeing it."

Common uses for BCC: sending a mass email to a list without exposing everyone's email address to each other (though an ESP is better for this), keeping a manager or assistant quietly in the loop on correspondence, or forwarding something to yourself for records without the recipient knowing.

One thing to watch: if someone on the BCC list hits "Reply All," they'll out themselves. The reply will go to everyone on the TO and CC lines, and suddenly everyone knows this person was secretly included. (Happens more often than you'd think.)

For marketing emails or newsletters, don't use BCC to send to a list. It looks unprofessional, your unsubscribe link won't work right, and mailbox providers will flag it as spam. Use a proper ESP instead.