The difference between "forum" and "social media" is how posts are sorted and displayed. HN and Reddit are focused on news, the newest stuff goes to the top an

The difference between "forum" and "social media" is how posts are sorted and displayed. HN and Reddit are focused on news, the newest stuff goes to the top and disappears after a day or two. Forums on the other side focus on topics. Threads with on going discussions go to the top. They never disappear, as soon as somebody makes a new post into a thread it goes back to the top. This means you can end up with extremely in depth and long ongoing discussions on forums that you'll never find on social media. It wasn't unusual to find threads on IMDB forums that spanned literally decades. Meanwhile on Reddit everything gets locked from any further participation after six months and becomes impossible to find after just a few days.