In terms of politics, one of the big fears that the Internet brings is the potential for radicalization of supporters at the extremes of the political spectrum. Indeed, the Internet allows them to find each other, confirm each other's radical views and in particular dream up conspiracy theories without being challenged by reality. And that is where it becomes dangerous. Think of the various terrorist movements in the 1970s in Europe, where members lived in something like reclusive communes. The Internet allows these communes to be virtual and thus recruit more members. Should we be worried?
Matthew Gentzkow and Jesse Shapiro say that the contrary is actually the case. They look at the segregation on news consumption and find that it is low for Internet news. It is higher than for offline news, as I would have suspected, but much lower than for face-to-face interaction. And it should thus be encouraging that people are moving more and more from face-to-face interactions to online interactions. I am thus reassured.