Zotero's Groups feature allows you to share references with other Zotero users online. This can be beneficial if you are working on a group project, are collaborating with peers, or wish to share resource information with a group.
Private groups allow you to work together without creating a public presence for the group. Your group, and those you invite, will be able to see your library - but the group will not be listed.
Public, Closed Membership (Recommended by the LRC Staff)
Closed-membership groups allow you to have a public presence, but also give you control over access. Anyone can see your library, but only those you invite, or whose request you have approved, can join.
Public, Open Membership
Open groups are just that - open. Anyone can see them, anyone can join them. File sharing is not allowed in public groups.