He coined the phrase "conspicuous consumption."

(1857-1929)
Thorstein Veblen is to economics what Jonathan Swift is to English literature: a master of the art of satire. Is is essential to effective satire that its message be ambiguous: the reader should never be sure whether the author is absolutely serious or just pulling his or her leg. That quality is certainly present in Swift's Gulliver's Travels and it is also present in Veblen's Theory of the Leisure Class (1899), The Instinct of Workmanship (1914), Imperial Germany and the Industrial Revolution (1915), The Higher Learning in America (1918),Absentee Ownership (1923), and his many essays. In fact, it is there in everything he wrote except The Theory of Business Enterprise (1904), Which is as near as he ever came to writing a conventional academic book.
No matter which of these books we open,
we find the idea that life in a modern industrial community is the result of a polar conflict between 'pecuniary employments' and 'industrial employments', between 'business enterprise' and 'the machine process', between 'vendibility' and 'serviceability'-
in short, between making money and making goods. There is a class struggle under capitalism, not between the bourgeoisie and the proletariat, but between businessmen and engineers. Pecuniary habits of thought unite bankers, brokers, lawyers and managers in a defense of private acquisition; in contrast, the discipline of the machine unites workers in industry and more especially the technicians and engineers who supervise them.
http://qed.econ.queensu.ca/walras/bios/veblen.html Veblen’s writing
Veblen developed a 20th century evolutionary economics based upon Darwinian principles and new ideas emerging from anthropology, sociology, and psychology. Unlike the neoclassical economics that was emerging at the same time, Veblen described economic behavior as both socially and individually determined and saw economic organization as a process of ongoing evolution.
This evolution was driven by the human instincts of emulation, predation, workmanship, parental bent, and idle curiosity. Veblen wanted economists to grasp the effects of social and cultural change on economic changes.
In The Theory of the Leisure Class, which is probably his best-known work, because of its satiric look at American society, the instincts of emulation and predation play a major role. People, rich and poor alike, attempt to impress others and seek to gain advantage through what Veblen coined "conspicuous consumption" and the ability to engage in “conspicuous leisure.” In this work Veblen argued that consumption is used as a way to gain and signal status. Through "conspicuous consumption" often came "conspicuous waste," which Veblen detested.
Much of modern advertising is built upon a Veblenian notion of consumption.In The Theory of Business Enterprise, which was published in 1904, at the height of American concern with the growth of business combinations and trusts, Veblen employed his evolutionary analysis to explain these new forms. He saw them as a consequence of the growth of industrial processes in a context of small business firms that had evolved earlier to organize craft production. The new industrial processes impelled integration and provided lucrative opportunities for those who managed it.
What resulted was, as Veblen saw it, a conflict between businessmen and engineers, with businessmen representing the older order and engineers as the innovators of new ways of doing things. In combination with the tendencies described in The Theory of the Leisure Class, this conflict resulted in waste and “predation” that served to enhance the social status of those who could benefit from predatory claims to goods and services.
Veblen generalized the conflict between businessmen and engineers by saying that human society would always involve conflict between existing norms with vested interests and new norms developed out of an innate human tendency to manipulate and learn about the physical world in which we exist. He also generalized his model to include his theory of instincts, processes of evolution as absorbed from Sumner, as enhanced by his own reading of evolutionary science, and Pragmatic philosophy first learned from Peirce. The instinct of idle curiosity led humans to manipulate nature in new ways and this led to changes in what he called the material means of life. Because, as per the Pragmatists, our ideas about the world are a human construct rather than mirrors of reality, changing ways of manipulating nature lead to changing constructs and to changing notions of truth and authority as well as patterns of behavior (institutions).
Societies and economies evolve as a consequence, but do so via a process of conflict between vested interests and older forms and the new. Veblen never wrote with any confidence that the new ways were better ways, but he was sure in the last three decades of his life that
the American economy could have, in the absence of vested interests, produced more for more people. In the years just after World War I he looked to engineers to make the American economy more efficient.
http://en.wikipedia.org/wiki/Thorstein_Veblen