Hacker News Reader

They are not new. but they have been growing over the last 10 years, in part because of the X Games.

I believe it's just that GoPro + Internet allows for more action sports footage from many more perspectives to be broadcast to a wider audience compared to what was available ten years ago. I know theberrics.com uses GoProp for a lot of their footage.

New in the sense that GoPro has opened access to them - we ride, climb, fall, swim from the persons perspective. I'd wager their perennial popularity on the youtubes drives interest/adoption in action sports