If your instructor has enabled discussion forum subscription, you can be alerted via email when new posts are made in your class discussion forums. The following instructionsIf your instructor has enabled the subscription feature, you can complete the following steps to receive emails when new posts are made to the forum.
1. Locate the discussion board. The link to the discussion board is usually accessible on your course menu.
2. On the discussion board page, click the name of the forum to which you would like to subscribe.
3. In the discussion forum, click Subscribe on the action bar.
4. When you have successfully subscribed, a green success message appears.
5. If you would like to unsubscribe from a forum, click Unsubscribe on the action bar.
6. When you have successfully unsubscribed, a green success message appears.
https://en-us.help.blackboard.com/Learn/9.1_2014_04/Student/090_Tools/Discussion_Board/010_Forums