Few days? Try since forever. As people increase the SNR gets larger. Even on reddit when it started, it was heavily tech focused, you'll find a comment that say

Few days? Try since forever. As people increase the SNR gets larger. Even on reddit when it started, it was heavily tech focused, you'll find a comment that says it's going downhill. Hard to say what the numbers on HN are like growth wise in comparison to reddit (which has their subscriber numbers on display).