In broadcasting, the term blackout refers to the non-airing of television or radio programming in a certain media market.[1]
It is particularly prevalent in the broadcasting of sports events, although other television or radio programs may be blacked out as well. Most blackout policies serve to protect local broadcasters (primarily regional sports networks) from competition by "out-of-market" networks that carry different teams, by only allowing viewers to watch non-national telecasts of teams within their designated markets (with television providers blacking out regional telecasts of teams that are outside their market; in turn, encouraging viewers to purchase subscription-based out-of-market sports packages), and by allowing teams to black out national telecasts of games that are also being shown by a local broadcaster.
By contrast, some blackout policies, such as those of the U.S. National Football League and English association football (soccer), serve to encourage attendance to games by respectively requiring that a specific percentage of tickets be sold in order for a game to be televised in the home team's market, or by enforcing a blanket prohibition on any telecast of football matches (regardless of where it is being played) during specific windows.
The term is also used in relation to situations where programming is removed or replaced on international feeds of a television service, because the broadcaster does not hold the territorial rights to air the programs outside of their home country.