The personalization debate was just heating up in 2002. In this article (PDF), Cass R. Sunstein notes that the power to personalize enables people to learn far more than they could before but that the increasing ability to filter in, and also filter out, information and opinions carries significant risks as well.
From September 2002:The Personalization Debate
Question: Emerging technologies have brought personalization to the forefront in the news media field and increasingly in other areas as well. What are the implications of personalized Internet use for news, for education, and for society?
a. Personalization is a broadening process that widens the horizons of the news consumer, the student, and the citizen. It represents a revolutionary shift in the balance of power between the information provider and the individual, allowing individuals to take an active role in sharing ideas, in pursuing a field of inquiry and learning a topic thoroughly, and in becoming a part of the dialogue of the democratic process.
b. Personalization is a fragmenting process that prevents unanticipated encounters and shared experiences. It represents a filtering mechanism, limiting the perspective of the news consumer, the student, and the citizen, increasing their ability to wall themselves off from topics and opinions they prefer to avoid, and as a result, endangering their awareness of world events, their education, and even democracy itself.
c. Both of the above.
For help in choosing a, b, or c, EDUCAUSE Review called on two scholars who have given this question much thought. Cass R. Sunstein, professor at the University of Chicago Law School and Department of Political Science, has written extensively on constitutional law, the First Amendment, and jurisprudence. His recent book Republic.com evaluates the consequences of new communications technologies for democracy and free speech and suggests a range of potential reforms to improve deliberative democracy and the health of the American republic. Walter Bender is executive director of the MIT Media Laboratory, founded in 1985 by Professor Nicholas Negroponte. Bender is a senior scientist, the director of the Electronic Publishing research group, and a member of the News in the Future consortium at the laboratory. As an original member of the Media Lab, Bender has been integrally involved in the personalized news projects that became known collectively as the “Daily Me.” (Bender's article can be found here.)