Is there a resource on how much karma you need to do what on HN and what the username colors mean? I assume green is new, blue is a couple months old and grey is even older?
Not that I'm aware of. Also, I've never actually seen blue, somehow. I believe that downvoting comes in around 500 at this time.
But green is not reliably "new". It tends to be strongly correlated to newly created accounts, but I've seen weird behavior (like a child comment is marked green... whereas the comment thread was started by the same commenter in gray in the first place), which leads me to believe there's something subtler going on. I thus have no idea what the difference in color is supposed to indicate at all.
