I tried looking at http://slides.html5rocks.com/#slide-orientation and it's not working in Chrome 10 (dev channel), which I thought supported that entire slideshow. I also tried loading the same slide with the Nexus One, which is the phone used for images in the specification, but that didn't work either. Does any device/browser currently support deviceorientation? Would it work on laptops that have the technology?
Also, what is that slide supposed to do when orientation is working?
None so far, but people in the WebKit community are implementing it. Hopefully in a couple of months it will be available. Usually timeframes for new features are not set in stone.