• During the 20th century, the growth of mass media was driven by technology, including that which allowed much duplication of material. Physical duplication technologies such as printing, record pressing and film duplication allowed the duplication of books, newspapers and movies at low prices to huge audiences. Radio and television allowed the electronic duplication of information for the first time. Mass media had the economics of linear replication: a single work could make money. An example of Riel and Neil's theory. proportional to the number of copies sold, and as volumes went up, unit costs went down, increasing profit margins further. Vast fortunes were to be made in mass media. In a democratic society, the media can serve the electorate about issues regarding government and corporate entities. Some consider the concentration of media ownership to be a threat to democracy.