There used to be a function available to do this, but it went away with the last "upgrade" and board rework after it crashed. It does indicate forums with new posts with a red icon to the left and the same within each forum, each topic with a new post since your last visit will also have a red icon to the left of the title and of course, all newer topics and topics with newer replies will always be closer to the top of each subforum. (other than the announcements and stickies which always come first.)
Dude: 5' 11" - 54: Started 04/01/04
Ramblin' along in P3 since June '05...
Eat real food. Not too much. Mostly plants. -- Michael Pollan