I first read this in the book Information Architecture for the World Wide Web (the Polar Bear book), by Louis Rosenfeld and Peter Morville (1998); of course this is another good book on web development (the 3rd edition is the most recent one).
Hayden White is a historian and professor at UC Santa Cruz and Stanford. This simple statement reflects classification's role in information management and processing (especially analytical processing). Classification is the basic, and the most important, technique to organize and understand information, thus gain knowledge from it. It is a critical success factor for website development; also an important skill for a knowledge worker in this information age. Read more about Craig Stroupe's ideas on White and his process of understanding. Or you really have some time you can read this paper by Barbara H. Kwasnik