Here is the recorded video featuring the presentation of Matt Mullenweg of WordPress with Dries Buytaert of Drupal discussing open source. Kudos goes out to the Schipulcon group for getting these two together for an awesome presentation. The audio is terrible until you hit the 4 minute mark. If you want to see a transcript for some of the questions you can read them on the Schipul Blog. Definitely watch from 32 minutes onward as that is when the audience starts asking some pretty good questions.