If you're a forum junkie like me you watch the forums like a hawk to see if anyone has replied to your post.
Well.... I'd love to be able to "Mark a Forum Read" after I've read the posts I want to read. Then I can refresh my page like a madman until the folder turns purple again.
It would also be great to have a "Mark All Forums Read" button. Then you could quickly clean the slate and await new posts without haveing to log out or wait 20 mins.
Visit your active.asp page. You will see this icon at the top left hand corner of the table . That is the "Mark All Forums Read" button. And when you press it, it will show you all new posts that have been made, since you visited the active.asp page. So you won't miss any posts.
There is no way to mark only one forum read because the new post status is purely based on the timestamp on the post and the lastheredate created when you logged in. Like Davio said, there is the "mark all forums read" icon in active.asp HOWEVER, that will change the lastheredate to the current date/time and reset the active.asp for the entire forum.
Only you. If you can wait for a few weeks, I'm developing a track Mod which does exactly what you want. It has the same functionality as active topics. You can track categorie, forum, topics and you mark them separately as "read".