It just has so much content. I've been enjoying this site a lot, but after the first couple posts of any tag, they start to be 2, 3 days old really quickly. Reddit was just a never ending stream of new content. I can't find anything else that satisfies my short attention span fueled desire to flip through links and comments.
Stop. Worrying. That. A. Post. Is. Old. First step is to turn off your feedtimes in your settings. Do it. Then comment on a post that is 2-3 days old. Or a year old. Or 2 years old. Why? 1. It will be reinjected into people's feeds. 2. It will show up in chatter. There are often posts that get reinvigorated. The only reason it doesn't happen more is because you are trained that comments old posts won't get read (or upvoted). So, stop thinking like that! Why does an article that's a year old have less value than one posted today?
I'll admit, it is hard to stop thinking like that. Everything online instills in us this sense of immediacy. People stop thinking about a post they saw on reddit at most 12 hours after they saw it, threads on 4chan "404" hours, sometimes even minutes after being made, replies on Twitter tend to make no sense after the initial tweet is a few hours old, people are deathly afraid of accidentally "liking" a Facebook or Instagram post that's more than a month old for fear of looking like a stalker. I think the internet as a whole is running our attention spans into the dirt. I also think it's deviously engineered to do just that but that's a tin foil hat conversation for another time.