That function is already available. If you enter the site, click on the community button (that takes you to the forums), scroll down to the forum you are interested in, look in front of the forum at the tip up, click on the tip up and it will show you all unread or new posts for that forum. If the tip up is set, no new posts. If the tip up is sprung, new posts. This is one of the things I love about this site!
Jay