Auto-updating usually doesn't quite work, especially when it comes to hot topics where many people post at about the same time. You'll be responding to something that may have been 10 posts back on a really popular forum. Not quite nice.

I don't really need a notification about whether or not other people have posted. I always see my post and usually check for errors afterwards, so that will just about always make sure I will notice it and if necessary edit my post.