His broad conclusions are 1. yes and 2. no.
Why do British blogs have fewer readers? Well, there are fewer Britons than Americans, and our press is less opinionated. Berger quotes Neil McIntosh from Guardian Unlimited saying:
"In this country we have an enormously diverse media. You can be offended by Richard Littlejohn on the right and George Monbiot on the left. You can find [right wing] Max Hastings and [left wing] Polly Toynbee in the pages of the Guardian. So where is the ground into which blogs can successfully move?"Ah, but we still have influence says Martin Stabe:
"What matters most is not reader numbers but who these readers are - the political analysts, the party activists, journalists looking for leads and story ideas. They are what marketing people call opinion leaders. So there is an argument that an elite readership is more important than a mass readership."