Written Explanation with Visuals:
Discussion pages provide an opportunity to collaborate with other teachers as you progress through the module. Each page will include a Description with a prompt for Discussion, and may also include Resources, just like Reflection Pages.
All users have the option to participate in the Discussion with their users only from your District, or with users from All Districts. If you are associated with a School or Cohort, you'll also have a tab with the option to discuss at that level. If you are associated with multiple Schools or Cohorts, you'll have a dropdown to select your desired group for discussion. Each of these options for discussion include your number of unread comments in parentheses.
A checkbox at the bottom of the discussion area gives you the option to subscribe to receive notifications when new comments are added. All users can manually subscribe or unsubscribe by checking/unchecking this box. Note, your subscription is specific to the discussion you've viewing, so if you subscribe to the discussion in the My District tab, you will not be automatically subscribed to the discussion in the All Districts tab.
Update: You can edit or delete your own discussion comments using the pencil and trash icons at the upper right corner of your comments, and you can direct-reply to another user's comment by clicking the reply icon at the upper-right of their comment. See above image for icon placement. Replying directly to a user's comment will send them a notification email.
Just like on Reflection pages, you can change the status of Discussion pages in the upper left corner, from Not Started to In Progress or Complete. Note that if a new tile is added to the module after you have received your micro-certification, this tile will be marked as "Attained" with a green dot status icon, instead of being marked as "Complete" with a green check status icon. The "Attained" status also appears on Discussion pages if you pass the Pre-Assessment for the module. This status indicates that you are note required to complete the tile, but you have the option to do so.