First, Jon Stewart sure seems like a fantastic guy. Smart, friendly, down to earth, funny the whole time on and off the camera. Maybe he should run for president sometime. I would vote for him. His only problem is that he is not so tall, and Americans grow their presidents tall.

Second, sitting in the studio, no matter how hard you to try, it is impossible to imagine that 2 million people are watching what you are doing (actually in my case 2,000,002 because my parents don't usually watch, but they were watching last night). Which is good if you are someone like me who is inherently anti-social and frightened by crowds. It certainly would be more nerve-wracking to do an interview in front of a live audience of 2 million people stretched out over the Mall in Washington.

Third, television, except maybe Charlie Rose, is a terrible medium for trying to talk about books. I had a long interview -- over 6 minutes -- but Stewart was asking hard questions that I couldn't give real answers to (essentially he wanted me to explain regression analysis, but to do it in 15 seconds). One key point in Freakonomics is that we try to show the reader how we get our answers, not just assert that we are right. On TV, there just isn't time to follow that path.

Fourth, it sure is nice to be in front of an audience that is dying to laugh at and respond to anything you say. (For instance, I'm not sure why, but the audience burst out laughing when I mentioned crack cocaine.) I wish the students in my 9 am undergraduate lecture were so responsive. Of course, if my lectures were one-tenth as entertaining as the Daily Show, I bet my students would be plenty responsive.