It’s related to notifications. The longer a user goes between being presented an opportunity to reply, a) the more time they will have had to think about the to

It’s related to notifications. The longer a user goes between being presented an opportunity to reply, a) the more time they will have had to think about the topic, b) the more likely they will be to write a complete response, instead of just enough to prompt a further reply, c) the less likely they will be to reply when a reply is not necessary. A good HN thread has fewer, comments (fewer than this one. :) )