Here's a perennial problem seemingly baked into how we humans organize ourselves.
On the one hand, we have a seemingly natural tendency to cluster ourselves into groups of relatively like-minded people. In fact, we can't have a conversation unless we share some assumptions and some values. In double fact, we can't learn anything except by assimilating the new into the familiar.
On the other hand, clusters of like-minded people tend to reinforce their own presuppositions, blinding them to new truths. They can form a self-congratulatory clique impervious to learning.
This is true not only of your friends and co-workers. It is true of civilizations as well: The civilization needs shared presuppositions to cohere but that cohesion can block cultural learning and advancement.
And at a much smaller scale, this shows up in the problem of diversity so common in corporations. The white guys don't really end up running most companies because they're so much smarter than everyone else.
One solution to this perpetual problem is to go out of our way to listen to people with whom we disagree. We may even need training in how to do so . . . thus were diversity programs born.
But, I believe, the terms of the problem are being changed. The problem isn't going away but it is more pernicious when the groups are more like M&M's than like a bowl of mixed nuts. If groups are hard to form, then maintaining their integrity--through exclusion--is more valuable and they develop hard candy shells. But if groups are as easy to form as scooping up a handful of mixed nuts, then it's easier to let other nuts in. If I can drift into and out of groups more at will--in fact, if I can "lurk" anonymously in a group--I can learn how to listen to them without having to declare myself one of them.
This is, of course, exactly the situation on the Web where joining groups is usually as easy as flicking your wrist. Nonce groups form around topics and sometimes even around disagreements. Of course, the very ease of clustering also often leads to flame wars that make a virtue of not listening. But, we can allow ourselves our moment of vituperative fun so long as in the next group we're actually willing to engage with others.
Nothing will get over the inherent contradiction between associating with those with whom we share assumptions and the need to bang up against alternative assumptions. But, insofar as the Web has made groups more fluid, the pain of the contradiction is greatly reduced, In fact, it is turned into play.
David Weinberger is the author of the upcoming book Small Pieces Loosely Joined. He can be contacted through his Web site evident.com