When reading forums I always like to make sure I have read the important topics. Some forums I am not interested in so I like to "Mark forums as read" from the main forum index. This saves a load of time and helps us focus on what we want to read.
It would be possible to have this image clickable so once double clicked, it marks the forum as read:
It would be good to have "Mark topics as read" in topic view as well but it's not important as having it in the main forum index in my opinion.