Hi,
For mouse only users: there's some arrow buttons on the left and right of the screen that follow the mouse height. So you don't need to move the mouse up and down to the top of the view port.
The keyboard arrow buttons are mainly there to alert people to the fact that you can use the keyboard to control navigation.
For touch screens it has a swipe left/right action to scroll over one column. It's not the best implementation of swipe... but it 'works'. I haven't got it working for touchpad swipes as of yet (eg for mac swipe left/right).
I think the issues that Sam mentioned with scroll wheel scrolling can be overcome and hopefully make scrolling better.
I have an early prototype of controlling the website via the new Joystick API chrome and firefox have implemented. But it's not enabled so far.
cu.