Once you start to understand what motivates people to engage with your content - whether that's a video, a blog post or some other experience - you can begin to build vibrant communities of participation. And today, since almost everything we do involves technology, it's getting easier and easier to determine what those motivators are.
I believe that TED Youth and YouTube together have great potential -- to inspire youth to use these powerful platforms to change the world and tell great stories. Moreover, as a psychologist who studies how these simple and easily accessible online tools shape youth values, I thought he missed an opportunity to inspire the youth who were so eagerly listening to his speech.
Though in some cases a "viral sensation" seems to occur overnight, the chances of a user's video becoming a sensation is (like many things) by chance. The amount of YouTube videos being uploading at any given moment is pretty awesome, but also decreases the likelihood that a random video becomes a hit.