Hacker News Reader

I'm guessing these are all comments made by accounts created within the last 24 hours.

Green accounts are new and have low karma.

No. Just took a random look at a couple of them, and one of the poster registered 5 days ago. I am guessing maybe 7 days?

It can't be that either, one person's account is 12 days old. Googling around, one source [0] suggested it counts only active days.