Sometimes the answer you would have given has already been posted, so it seems pointless to repeat someone else. Many people, however, don't seem to read other people's posts and the same things get said again and again.
Sometimes the question needs specialist or personal knowledge, so that cuts down the number of replies.
My fav section is news. I add the occasional reply but mainly I enjoy the personal views, venomous replies and how opinions never seems to change, however well they are "proven" or otherwise!