There is a notification setting for "Announcement Created By You" so that a teacher receives an email notification of their own announcement. There is NOT a notification setting so that a teacher receives an email notification of their own discussion post/entry.
Add a "Post Created By You" notification setting so that a teacher has the option to receive an email notification of their own announcement. This would allow teachers to create a repository and history of their discussion posts from which to draw for future courses and/or writing projects.