On Yahoo!Blog, while presenting its new MyWeb2.0:
The answer a web search engine delivers is what it believes is the correct answer for the majority of users – often referred to as “the tyranny of the majority”. For example, when you search for ‘apple’, the first result on most search engines is Apple Computer. But you may have been searching for information about the fruit or Apple Records.
This is a point I’m making since some years and so I totally agree that this is a problem of current search engines and I totally agree that considering personal trust networks of users is the solution to go (actually this is my my PhD research topic).
But I want also to point out, as I already did some time ago, that on the other extreme (total personalization) there is another, maybe bigger, risk: “the daily me”.
If you only see web sites, opinions, movies, etc of people you already agree with, you will never ever meet new, unexpected points of view, you will never ever need to argue your points with someone that thinks different (and possibly change your mind, at least a little bit), you will simply exacerbates your opinions, you will end up not even being able to understand the language used by people that are not in your “community” of like-minded friends!
If you are an anarchist speaking/reading only other anarchists, you will strengthen your opinions, they will become more extreme. Or if you are a catholic orthodox, or … The same is true for every group: liberals watching and reading mostly or only liberals; moderates, moderates; conservatives, conservatives; neo-Nazis, neo-Nazis. The resulting divisions run along many lines–of race, religion, ethnicity, nationality, wealth, age, political conviction, and more. Most whites avoid news and entertainment options designed for African-Americans. Many African-Americans focus largely on options specifically designed for them. So too with Hispanics

This will produce extremism and fragmentation of society and could have terrible, violent consequences.
The great book of Cass Sunstein Republic.com analyses this risk and more importantly tries to suggest a range of potential reforms to correct current misconceptions and to improve deliberative democracy and the health of the American republic.

(…)
First, people should be exposed to materials that they would not have chosen in advance. Unplanned, unanticipated encounters are central to democracy itself. Such encounters often involve topics and points of view that people have not sought out and perhaps find quite irritating. They are important partly to ensure against fragmentation and extremism, which are predictable outcomes of any situation in which like-minded people speak only with themselves. I do not suggest that government should force people to see things that they wish to avoid. But I do contend that in a democracy deserving the name, people often come across views and topics that they have not specifically selected.

Second, many or most citizens should have a range of common experiences. Without shared experiences, a heterogeneous society will have a much more difficult time in addressing social problems. People may even find it hard to understand one another. Common experiences, emphatically including the common experiences made possible by the media, provide a form of social glue. A system of communications that radically diminishes the number of such experiences will create a number of problems, not least because of the increase in social fragmentation.

I think it is time that everyone of us (especially those involved in creating personalized services, and hence in this case, especially Yahoo!) should start thinking about this problem before we are too ahead in the future. What do you think?