Only five posts showing...hmmm. Not sure.
I really only use it for seeing 'if' a new reply has been posted, rather than where/what as then I immediately click on the forum and go through clicking the boards where there are new posts.
Also, a couple of links I never use but are very useful are the...
Show unread posts since last visit. Show new replies to your posts....links at the very top of the page!
Alternatively, there is a 'scrolling' option that adds a scrollbar and can show any number of unread posts but when you do that it only has enough height to show 3 which I thought looked worse.