As Defined by Appropedia:
The majority world (sometimes capitalized as Majority World) is a term used in preference to the largely inaccurate, out-of-date and/or non-descriptive terms developing countries, third world and the “South”. In the early nineties, Bangladeshi photographer Shahidul Alam began advocating for a new expression “majority world” to represent what has formerly been known as the “Third World.” The term highlights the fact that these countries are indeed the majority of humankind. It also brings to sharp attention the anomaly that the Group of 8 countries—whose decisions affect majority of the world’s peoples—represent a tiny fraction of humankind.
Majority world defines the community in terms of what it is, rather than what it lacks.
The term LDCs (Least Developed Countries) is more accurate than most of the alternatives, but may be seen as having strong negative connotations that reinforce the stereotypes about poor communities and represent them as icons of poverty. There is also the question of summing up a nation which may have great cultural heritage as less developed, by considering only the economics development.
More strident critics of the Western role in these nations make more damning criticisms of the terms third world, developing country and LDCs: that they hide histories of oppression and continued exploitation. It is sometimes argued that economically poor countries of the world are invariably countries that have been colonized, and continue to be colonized through globalized forms of control.
The labels also hinder the appreciation of the cultural and social wealth of these communities. Though these terms are still used, there is an increasing feeling within the communities themselves that these terms are inappropriate. The term majority world may be seen as challenging the West’s rhetoric of democracy.