Cluetrain Manifesto and Its Effect on Advertising

#2 Markets consist of human beings, not demographic sectors. (95 Theses)

This statement is one which I believe presents a challenge to advertisers in this day and age. Approaching a market as individuals and not just a collective demographic of people is something which I believe the advertising industry is attempting to achieve. However, I find it unusual that in advertising courses and even advertising firms, demographic studies are still researched and applied to campaigns. I took a course in advertising last semester. A good majority of the class was spent on identifying demographics and learning how to cater to those specific demographics.

Which brings me to this thought: Is it possible to cater to individuals or does there have to be some element of generalization (demographic analysis)?