Once you are in a forum, click the "Manage My Subscriptions" link on the left-hand side. There, you can specify the email address the notification is delivered to, change the frequency, or unsubscribe to forum notifications. "Immediate" frequency delivers a notification each time someone posts to the forum. "Daily Digest" gives you a notification Monday - Friday at 8:00 a.m. each day of the posts that were submitted since the last notification you received. "Weekly Digest" notifications are sent at noon on Fridays with a list of all posts throughout the week.