Basic Argument:  Modern culture industry, under the influence of mechanical reproduction, produce standardized commodities which serve to homogenize/massify their consumers.  Even high arts get to be sacrificed in thie barbarity of style (or lack of genuine style).  

The essay published in mid-1940s.   "Adorno and Horkheimer were refugees from Nazi Germany living in the U.S.  Hitler's totalitarianism and American market system are fused in their thought--all the more easily because, for them as members of the German (or rather secularized German Jewish) bourgeoisie, high culture, particularly drama and music, is powerful vehicle of civil values" (editor 29).  
  

Films, radio and magazines make up a system which is uniform as a whole and in every part.  (30)

  reasons for standardization (31-32)

The technical contrast between the few production centres and the large number of widely dispersed consumption points is said to demand that standards and planning by management.  
A technological rationale is the rationale of domination itself.  It is the coercise nature of society alienated from itself.  
The technical and personnel apparatus . . . itself forms part of the economic mechanism of selection.  
Culture molopolies are weak and dependent in comparison.  They cannot afford to neglect their appeasement of the real holders of power.  
  

classfication of one genre and of audience: Marked differentiation such as those of A and B films, or of stories in magazines in different price ranges, depend not so much on subject matter as on classifying, organizing, and labelling consumers.  (32) 
integration of different media: The varying budgets in the culture industry do not bear the slightest relation to factual values, to the meaning of the products themselves.  Even the technical media are relentlessly forced into uniformity.  
 

  Real life is indistinguishable from the movies.  . .  .The stunting of the mass-media consumer's power of imagination and spontaneity.  
[The movies] are so designed that quickness, powers of observation, and experience are undeniably needed to apprehend them at all; yet sustained thought is out of the question. . .  they react automatically. 
The culture industry as a whole has moulded men as a type unfailingly produced in every product.  (34) 
There is laughter because there is nothing to laugh at.  . .  .The pleasure industry never fails to prescribe [fun].  It makes laghter the instrument of the fraud practised on happiness.  (39)
Pseudo individuality is rife: from the standardized jazz improvization to the exceptional film star whose hair curls over her eye to demonstrate her originality.  (41)

Related Idea: 
parts interchangeability  － 車子與個人認同．
汽車是Adorno所批評的文化工業的代表，因為車子生產規格化的兩大特色是假個別化（pseudo-individualization）及零件交換性（part interchangeability）．對Adorno而言，不同廠牌不同車型所擁有的個別性，是虛假的，因為這種個別性來自表面的裝飾，實際上不同車的主要零件多半是可以互換的（cf. Grendon 20）。在廣告的推銷手段下，消費者對這種個別化的虛假，往往渾然不覺。於是，擁有不同的車，便是擁有不同的社會地位。
  
如Watkins所指出，車子及其他大眾消費品的功用即在重新定位消費者："The apparent emptiness of the marketing of the quad four nevertheless intervenes toward a profound redistribution of position, not despite but because of the lack of differnence with respect to competitors' engines" (162).
 
  True art: negativity (vs. culture industry as the negation of style)

The great artists were never those who embodies a wholly flawless and perfect style, but those who used style as a way of hardening themselves against the chaotic expression of suffering, as a negative truth.  (37)
The secret of aesthetic sublimation is its representation of fulfillment as a broken promise. (38)  (v.s. culture industry, which does not sublimite; which represses.)   More on Adorno's view on Art.