The Forum feature appears within a group. Groups may use the forum to continue discussions of seminars, communicate with one another about how they are using the Hub's features, etc.
The highest level of organization in the forum is a Section. Below this are Categories, followed by Discussions. A discussion is the actual thread of posts. You can group similar discussions under the same category, and related categories in the same section.
When posting to a discussion thread, you can include links and simple formatting using the buttons at the top of the text entry box. You can attach images by clicking "Browse..." below the text entry box.
To receive email notifications when someone posts to the forum, click "Forum" on the left group menu, then scroll to the bottom of the page, check the box by "Email forum posts," and click Save.