Keyboard navigation is a feature that's asked for rather often. Very basic navigation was possible with the arrow keys but we just pushed an updated which makes your keyboard much more powerful.
See for yourself! You can use the keyboard to jump between sections of the site, navigate between articles and take action on them. The shortcuts are very similar to Google Reader's shortcuts so if you were using them with Google Reader you should feel right at home.
On any page, hit the
? key to see all combinations.