Keep in mind navigation keys shouldn't be any key that inputs a character, I can kill the event listener when textarea gets focus but even so it's not foolproof.
Example I think it has focus then I press 'r' and the page refreshes and I lose everything I typed. Or at the very least I'm back to the top of the page.
Think about what happens in game when we type without pressing enter. I get 10 interfaces open and I have no clue how to close half of them. It would be inflicting the same curse onto the forums imo.
Keys for navigation can't be alpha numeric, can't be keys used by the browser (arrows or function keys) and need to be easily accessible.
Combinations like (ctrl + shift + R) are just not convenient for most people.
My biggest concerns are accidental key presses though.
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~ Blame Rowley if it doesn't work ~