Internet Direct (Indy) Version 9.0.1 Beta
TIdMessage.BccList
Indicates blind carbon copy recipients for the message.

property BccList: TIdEmailAddressList;
Description
BccList is a TIdEMailAddressList property used to store email address of recipients that will receive a carbon copy of the message, but do not appear in the "To:" headers for the message.

BccList is often used for mailing list applications, where members of the mailing list should receive a copy of a message addressed to the list.