This practice declined with the advent of photocopying and other electronic means, although it is still used in some contexts; for example, manual receipt books commonly have a sheet of carbon paper supplied, in order that the user can keep an exact copy of each receipt issued.
However, the term "carbon copy" has found renewed use with the growth of the Internet, even though its original meaning does not apply. In the context of email, it refers to the practice of sending a message to multiple recipients. It is commonly used in mailing lists.
The CC addresses, however, are not hidden from the recipients, and this may not be a desirable thing, depending on the situation. To circumvent this, the header field BCC or blind carbon copy was created.