Content can be associated with one or more groups. Consider a site with two groups (see diagram below).

Page 1 has only been published in Group 1 while Page 2 has been published in Group 1 and 2. Page 3 has only been published in Group 2. The ability to associate content with different groups can be very useful for organizing content and collaborating within, and sharing between groups.

Note that under the default configuration there is no restriction on what site users and the public can see. By default, anonymous users can view groups, the memberships of groups and the content within groups.