It was cute for about 2 seconds, then got incredibly annoying.
I get the feeling that it's more satisfying when it's on your own keyboard, but it's definitely annoying on another person's.
I'll bet he can't even hear it.
He turns it on at the beginning and says it's because he likes having audio feedback.
It's like playing a video game, I'd imagine. The sound effects are the bane of everyone's existence but your own. Seriously though, you don't play your _game boy_ in public without headphones; let alone present while playing one! I'm amazed -- so, so tempted to turn of the preso even if I was fascinated by the content.
Brenden Gregg was already my favorite Linux internals experts. This would've taken him to the top of the list if he weren't already there.