In a way it does not exist any more. Most of the threads are started by 4chan-GPT yes this is a thing and most replies to threads are 4chan-GPT. They uses 4chan passes to allow proxies and not have to deal with a craptcha. Anyone could start their own chan, implement GPT bots and have the same level of popularity. I would wager a dozen HN'ers could implement this in a day. I think the goal on 4chan is controlling the narrative. My question would be, would HN'ers also use bots to control the narratives on their chans or create the same daily and weekly threads?
I doubt GPT is posting NSFW content. I think /b/ is mostly teen boys on the cell phones at school. Prior to 2012 it was diverse porn but then it started to lean heavily into gay porn. I don't know what to make of that. Perhaps Pornhub does not have enough gay porn and they are filling the void?
I don't see that much gay porn on there. The most popular threads seem to be teens that may or may not be 18, trans girls, chubby girls, and girls that you know personally. Then there's the AI porn which is often furry or children.