Your talks were my favorite parts of both SS08 and SS09. I think many other "unprepared" talks are given by other speakers simply trying to imitate your style (with both less humor and less content).
The point wasn't aimed at any one person. I've probably seen 50-75 speakers present this year, and lately I've heard the "I haven't prepared anything" declaration more than usual. Startup School was my last conference of the year so I felt now would be a good time to sum up the observation.
I thought all the talks at Startup School were excellent. I stayed for the whole conference - from pg's opener to Mark's closer. I learned a lot.
Interestingly I enjoyed Paul's talk more than Jason's.