Carbon copying is the technique of using carbon paper to produce one or more copies simultaneously during the creation of paper documents. A sheet of carbon paper is sandwiched between two sheets of paper and the pressure applied by the writing implement to the top sheet causes pigment from the carbon paper to make a similar mark on the copy. More than one copy can be made by stacking several sheets with carbon paper between each pair. Four or five copies is a practical limit. The top sheet is the original and each of the additional sheets is called a carbon copy. The use of carbon copies declined with the advent of photocopying and electronic document creation and distribution (word processing).
It is still common for a business letter to include, at the end, a list of names preceded by the abbreviation “cc:”, indicating that the named persons are to receive a copy of the letter, even though carbon paper is no longer used to make the copies. The contacts that are listed as adressed “to” are required to read the mail and take further actions (if needed), where those listed in “cc” are only assumed to read the mail (when the time allows it). The aspect of the “blind carbon copy” (bcc) adds an extra perspective where one could be informed without any of the other contacts to even know!
Practically Spoken : Privacy
Need to mail a bunch of people? Add yourself in the “to” list and -all- the other contacts as “bcc”. This way you avoid to violate other people’s privacy by exposing their private email accounts!