From the Wikipedia:
Mass media is the term used to denote, as a class, that section of the media specifically conceived and designed to reach a very large audience (typically at least as large as the whole population of a nation state). It was coined in the 1920s with the advent of nationwide radio networks and of mass-circulation newspapers and magazines. The mass-media audience has been viewed by some commentators as forming a mass society with special characteristics, notably atomization or lack of social connections, which render it especially susceptible to the influence of modern mass-media techniques such as advertising and propaganda.
On Sensei's Library we naturally limit the discussion to:
Example: a magazine article about Go, like the excellent 2 page article in the Economist somewhat recently (2005)