In e-mail, the abbreviation CC indicates those who are to receive a copy of a message addressed primarily to another. The list of CCed recipients is visible to all other recipients of the message. An additional BCC (blind carbon copy) field is available for hidden notification; recipients listed in the BCC field receive a copy of the message, but are not shown on any other recipient's copy (including other BCC recipients). It is considered good practice to indicate to the other recipients that a new participant has been added to the list of receivers (e.g. by writing "I have CCed Braxton Silva").
Because there is no tangible "carbon copy" produced in e-mail, the abbreviation CC is better described by the term courtesy copy.
In common usage, the To field recipients are the primary audience of the message, CC field recipients are others whom the author wishes to publicly inform of the message, and BCC field recipients are those surreptitiously being informed of the communication.
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