A group is a collection of items usually related to a specific area of interest. You can create groups as a way to organize and share your items. As a group owner, you decide who can find the group, who can join, and who can contribute content. You also have control over items shared with the group and can invite others to join who have the same type of account you have—organizational or public—even if your group doesn't accept membership requests. Group owners can also promote other group members to group managers, which allows them to perform many of the tasks that owners perform on the group.
Groups that allow others to join the group and contribute items are a useful way to collaborate. For example, you're a biologist working on an international bird habitat map template. You search for groups whose members are sharing local bird habitat data that you can use. You can join the group and share your template. Together, your group can create a standardized international habitat map with rich local data layers.
Groups can also be used to organize specific types of data and users. For example, a group dedicated to imagery analysis may contain only hosted imagery layers, and only members with privileges to perform imagery analysis will be invited to join.
Administrators can configure the website by using groups to feature content on the home page and gallery and build custom galleries for basemaps and apps.
Within an organization, groups can be used to allow members to work closely together on projects. Administrators can also create groups that allow members of the group to update items shared with that group. These shared update groups are useful for shift workers in operations centers who need to update maps underlying their apps and dashboards and other situations where multiple people need to update the same item. Members of these groups can also edit hosted feature layers that have been shared with the group with full editing control even if the layer is not editable. For example, a public hosted feature layer that isn't editable can be shared with the group, and members of the group will have full editing control of the layer.
If your organization is in a partnered collaboration, you can use groups to share content seamlessly with other organizations. Groups that allow members from other organizations to join can promote members of partnered organizations to group managers. Group managers can add other members of their organization to the group.