When creating Discussion, discussion owners have possibility to define access of Discussion on submission form by setting:
Public - Controlled access
Public - Open access
Private - invitation only.
This option enables closed dialogue between group members important for brainstorming.
Discussion owner can change the access privileges to Discussions in two ways:
1. via option Edit located below the discussion’s description
2. by clicking on the dark velvet button on the right side of the Discussion page view Manage members.