Comment by grumbel

Subreddit threads are sorted by time and ratings, old style forum threads are sorted by activity. You can't bump a thread on Reddit.

This leads to forums having threads that last years or decades, while on Reddit nothing lasts longer than a day or two. Points also didn't exist in old forums and even for those that have them now, they are more decorative than functional.

With a forum it's much easier to keep track of what you read, you can see the new threads easily and be done with them when you read them. With Reddit everything gets reshuffled all the time. Even sorting by "New" doesn't help, since that only takes the first post in a thread into account, and doesn't bump it when a new reply arrived.

All that said, I much prefer threaded discussion, a lot of forums become unreadable when they just put all posts into a linear feed.