I've been messing about with the groups functionality to check out the various features and will update this if I find anything worth noting. 1. Privacy Using my mod account to create and my non-mod sockpuppet account to test, I have created a private group. To do this, select 'Invite only' under Group Type and (vital) 'Users must join to view the content'. This means that your group appears like the below to non-members and site guests: You'll note there's no 'join' button on the main page: You can change both group types and view options using the 'edit' button on the main groups page - note: Group Leader only.