Some clarification on Follow, Following and Followers. You can sign up to Follow any Forum category, such as "Missions and Events". You will then be notified, via email, of new posts or comments to the posts.
You can also have individual registered members Following your posts or you can be a Follower of their posts. When you are a Follower, you will be notified, via email, every time they post something, regardless of where it is posted in the Forum.