Private groups: Only members of the group can view and participate in group discussions and the group's portfolio. Non-members can click on the Members tab to view avatars for each member or click on the Overview tab to see the group owner's picture and those for the most recent members to join. From this page you can click the “Request Membership” tab to send a request to join this group.
Public groups: Only members of the group can participate in discussions and the group's portfolio, but anyone can read the group's discussions and view the portfolio. Non-members can click on the Members tab to view avatars for each member or click on the Overview tab to see the group owner's picture and those for the most recent members. From this page you can click the Join tab to send a request to join this group.
Remember: When creating a group you must designate the group as either public or private. This designation cannot change after the group has been created.