You could also be slower and more thoughtful and deliberate about conversation. You could think about what someone has to say while you were mowing the lawn or something, and reply back with something thoughtful instead of knee-jerk. They were also more topical, while modern social media is like 90% memes and shitposts (and I'm as guilty as anyone).

It was less performative. A place like this, sometimes folks don't care about the person they are responding to, they are speaking to other readers. Sometimes OP is just a soapbox to shout something unrelated to their post.

But also due to the small sizes, even pseudonyms were well known. People got to know you and understand your words in a given context. You could use sarcasm freely, for example. Now if someone uses sarcasm you have to check their history to see whether they are funny or crazy.

it feels like most users lose interest in posts and comment discussions very quickly, usually less than a day

I think this is because everything is combined into a single stream. Remember how in forum threads every time one person said something it would push the thread back to the front so everyone saw it again? Social media doesn't do that any more. If you had read the most recent comment in the more recent thread, you're done reading until someone posts something. Here in ADHD land, there is an eternal stream of new content — no going backwards. You could probably delete posts older than 30 days and 98% of users would never know.

Again, I'm as guilty as anyone there. I sort posts by new. I look back at the posts I've made over the last day and look at other comments, but after my post ages to 1d, I assume the post is done and almost never revisit.