I will have to disagree. Or rather, I think that while some bubble are pretty closed, some are very permeable. I'll take Hacker News for example. Although some

I will have to disagree. Or rather, I think that while some bubble are pretty closed, some are very permeable. I'll take Hacker News for example. Although some people complain about the fact that there are strong biases on HN, I actually think that it is not that bad, and there are plenty of topics on which the community is divided (on top of my mind: internet piracy is acceptable vs bad, windows is a good tool vs it sucks, google is evil vs it is awesome, linux will never be a good desktop environment vs it will, etc..). I think that there is a distinction between bubbles that are created around certain opinions (windows is bad + piracy is good + linux rocks) and bubbles that are organized around values (I disagree with you but I like debating with you + I like to learn about different subjects + etc..).