> His engaging with people there on a one-to-one level seems to exactly disprove the idea that it's an echo chamber that no one's paying attention to.
Except, you know, for the part where he calls it an echo chamber that no one is paying attention to: "It makes me feel like everything I’ve posted over the past four years on Twitter, Jaiku, Friendfeed, Plurk, Pownce, and, yes, Google Buzz, has been an immense waste of time. I was shouting into a vast echo chamber where no one could hear me because they were too busy shouting themselves."
Look at a Twitter search for @LeoLaporte to see all the people responding to him and/or trying to engage with him, or look at his Twitter stream to see him interacting with people himself. For that matter, look at all of the people commenting on his Buzz postings directly (e.g. http://www.google.com/buzz/laporte/iGbULnn1UMH/Its-funny-bec...)
None of that squares very well with the echo chamber claim.
Except, you know, for the part where he calls it an echo chamber that no one is paying attention to: "It makes me feel like everything I’ve posted over the past four years on Twitter, Jaiku, Friendfeed, Plurk, Pownce, and, yes, Google Buzz, has been an immense waste of time. I was shouting into a vast echo chamber where no one could hear me because they were too busy shouting themselves."