Mainstream media (MSM) is mass media that influences a large number of people and both reflects and shapes prevailing currents of thought. It may be contrasted with alternative media which may contain content more dissenting thought. Large news conglomerates, including newspapers and broadcast media, which underwent successive mergers in the U.S. and elsewhere at an increasing rate beginning in the 1990s, are often referenced by the term. This concentration of media ownership has raised concerns of a homogenization of viewpoints presented to news consumers. Consequently, the term mainstream media has been widely used in conversation and the blogosphere, often in oppositional, pejorative, or dismissive senses, in discussion of the mass media and media bias.