In this TED talk, Chris Hadfield speaks about his experiences as an astronaut on the International Space Station and how they relate to overcoming fear. Basically the message I took from the video is that fear holds us back, and that overcoming it can allow us to have some of the most amazing experiences of our lives.
It's a message that couldn't really be considered new. Much fewer of us would care to watch a video about overcoming fear if it didn't include a famous astronaut. While it's Chris Hadfield's fame that attracts people to the video, it's his stories, told so visually and in so much detail, that makes this talk and keeps people watching it for the entire eighteen minutes.
Also, if his astronaut stories didn't make him cool enough, he finishes off his talk singing "Space Odyssey", by David Bowie.