Chatter Group Setting

Chatter Group is awesome tool for collaboration, it let you collaborate with specific people. For example, if you're working on a team project, you can create a group for your team to share project-related files and information. You can join up to 100 groups, and your company can have a total of 10,000 groups.

Few note to take for Chatter Group:

• When you create a Chatter Group, you can set the level of access of the group.
• Chatter groups have different levels of access: Public, Private, Unlisted and Allow Customers.
• To know the level of access for the Chatter Group, click on Chatter tab | Click on Groups on the left side | Click the name of the group | Click on Group Settings link.

Public Chatter Group

• Any users can see it.
• Any users can post on it.
• Any users can comment on it.
• Any users can join it.

Private Chatter Group

• Users must ask to join or be added by the group’s owner or manager.
• Only group members can see and add posts, comments and files.
• Users with the “Modify All Data” and “View All Data” permission can see, join, update and post on it.
• Users with the “Manage All Data” permission can also change group settings.

Unlisted Chatter Group

• Only group members and users with “Manage Unlisted Groups” permission can see and add posts, comments and files.
• Users cannot ask to join. They must be invited by the group’s owner or manager.
• Offers more privacy compared to private group
• Non-members cannot see or access unlisted groups in list views, feeds and in search results.
• This is not enabled by default. The system admin should click on Setup | Customize | Chatter | Settings | Edit button | tick Enable Unlisted Groups” checkbox under Groups section | Save.

Private or Unlisted Chatter Group with “Allow Customers” option enabled

• The group’s owner and manager can invite customers to join the private or unlisted group.
• You can easily identify groups with customers by the orange upper left corner of the group photo
• The “Allow Customer Invitations” must be enabled: Click on Setup | Customize | Chatter | Settings | Edit button | tick Allow Customer Invitations check box under Customer Invitations section | Save.

Reference: 

• Chatter Groups Overview
• Create Chatter Groups