The new Message Board upgrade allows you to subscribe to any forums, and be alerted via email whenever a new message is posted. For instance, you might find it helpful to subscribe to the "Announcements" forum, to be alerted when new systems upgrades are available. Or perhaps you're a food photographer, and want to subscribe to that forum.
To get forum posts by email, simply visit the forum you're interested in (when logged into the message board), and scroll down to the bottom of the page. There, you'll see "More Options", and you can choose to have the Message Board send you an email whenever a new topic is posted.