Brief Explanation (author credit)

Karl Marx's analysis of appropriation as it is organized in what he calls the capitalist mode of production suggests that it is the changes in the mode of appropriation associated with the development of capitalism that have led to the emergence of a distinctive consumer culture in modern societies.  Lury writes:

For Marx, the mode of appropriation is the critical site where human societies develop their distinctive characters. It is through the activity of labour, the use and adaptation of natural resources, that human consciousness comes to be what it is. This means that human consciousness is realized or object)fied in the material products of labour. This is why the product of labour - the material artefact or good - is so central for the self-understandings of individuals and society generally. Material culture, for Marx, is the objectification of social consciousness. Under a capitalist mode of production, however, this objectification is turned against people.
This line of argument starts from the distinction that Marx made between appropriating or producing something for one's own direct or immediate use and producing something within an alienating division of labour that is created solely to be exchanged on the market. This latter process is the production of goods as commodities. . . It is the special features of objects as commodities which, it is believed, explain the distinctiveness of consumer culture as a type of material culture.

Marx noticed a number of features of the good as commodity that later observers have argued underpin the nature of modern consumer culture.   Among these features are the "enigmatic" quality of the commodity.  Marx adopted the phrase fetishism of commodities  to describe the "mysterious" process by which the external appearance of goods conceals the story of who made them and under what conditions.

Leiss et. al describe this process well:
Commodities are. . . a unity of what is revealed and what is concealed in the process of production and consumption. Goods reveal or 'show' to our senses their capacities to be satisfiers or stimulators of particular wants and communicators of behavioural codes.  At the same time, they draw a veil across their own origins; products appear and disappear before consumers' eyes as if by spontaneous generation, and it is an astute shopper indeed who has much idea about what most things are composed of and what kinds of people made them.

Some argue that the veiling tendency of commodity fetishism has merged with recent trends in international capitalism in a way that is particularly destructive.   These critics point to the fact that as the first world increasingly purchases commodities from the third, the less likely it is that consumers will know of the conditions under which goods are produced -- facilitating exploitation on a new scale. See, for example, this article about the toy industry.  

Lury continues:

But, you may ask, do consumers need to hear this story? In being deprived of it, are they experiencing a systematic distortion of communication within the world of goods itself? Marx suggests that they are. He argues that in market societies, commodities not only hide but come to stand in for or replace relationships between people. The (presumed) unity between production and consumption is broken. People's thinking about themselves and others is distorted by a fetishism, in which beliefs about the material products of labour - artefacts - are a substitute for an understanding of the social relations which made the production of the goods possible. Marx writes: 'The object that labour produces, its product, stands opposed to it as something alien, as a power independent of the producer' . A related term to describe this process is reification, which means a process of making a product or object thing-like. As a result of this process, the social relations represented in an object come to appear absolutely fixed or given, beyond human control ...

A related point made by many Marxists is that the fetishism of the commodity in modern society is strategically manipulated in the practices of packaging, promotion and advertising. Through packaging, promotion and advertising, goods are said to be fitted with masks expressly designed to manipulate the possible relations between things on the one hand and human wants, needs and emotions on the other. Adorno (1974), for example, speaks of how, once the dominance of exchange-value has managed to obliterate the memory of the original use-value of goods, the commodity becomes available to take up a secondary or ersatz use-value. Commodities become free to take on a wide range of cultural associations and illusions; this is the basis for what has been called commodity aesthetics. Advertising in particular is said to be able to exploit this freedom to attach images of romance, exotica, furfilment, or the good life to mundane consumer goods such as soap, washing machines, cars and alcoholic drinks. These images or masks fix the ways material objects are able to act as carriers of meaning in social interaction. They encipher goods in symbolic codes that consumers cannot resist.