a signal imbedded in digital content that could interact with equipment that has been engineered to recognize it
a single bit added to the data stream of broadcast DTV programming
A technology being pushed by the MPAA that embeds a digital sequence into TV signals that will prevent unauthorized redistribution.
A broadcast flag is a set of digital bits sent with a TV program to prevent digital copying of the content on the consumers end. It will not change the way you see a program, but instead will be hidden to the viewers eye. Broadcast Flags were initially created by Fox, but soon thereafter adopted as a part of the ATSC standards. The MPAA is pushing the FCC to implement broadcast flags so they can allow stations to broadcast their content without the fear of people making their own personal, digital copies.
A broadcast flag is a set of status bits (or "flags") sent in the data stream of a digital television program that indicates whether or not it can be recorded, or if there are any restrictions on recorded content. Possible restrictions include inability to save an unencrypted digital program to a hard disk or other non-volatile storage, inability to make secondary copies of recorded content (in order to share or archive), forceful reduction of quality when recording (such as reducing high-definition video to the resolution of standard TVs), and inability to skip over commercials. In the United States, new television receivers using the ATSC standard were supposed to incorporate this functionality by July 1, 2005, but a federal court struck down the Federal Communications Commission's rule to this effect on May 6.