Lawyer shit.
Everyday, I send email out that I have to send a 'blind carbon copy' to the other parties involved.

My firm is hired by A who is hired by B to sue C.

Every email sent to C has to be BCCed to A, so they know what is happening step by step on the case, but without C knowing I am reporting on every step. A then forwards the email with their own report to B, so that B can see that A is doing their job by hiring a law firm to sue C.

Before the age of computers, when typewriters were used for everything, carbon paper was used to make carbon copies of anything you typed. A carbon copy should show at the bottom of the page CC:(insert person's name). A blind carbon copy is blind because the first recipient does not see that a copy is going to anyone else, nothing typed at the bottom of the page.

Now, CC and BCC are buttons on email programs, and few people remember why.