Active Directory uses objects to represent network resources such as users, groups, machines, devices, and applications.
It uses containers to represent organisations, such as the marketing department, or collections of related objects, such as printers. It organises information in a tree structure made up of these objects and containers, similar to the way the Windows operating system uses folders and files to organise information on a computer.

Figure 1: Active Directory organises information hierarchically to ease network use and management.

In addition, Active Directory manages the relationships among objects and containers to provide a single, centralised, comprehensive view. This makes resources easier to find, manage, and use in a highly distributed network.

The Active Directory hierarchy is flexible and configurable, so organisations can organise resources in a way that optimises their usability and manageability. In Figure 1 above, containers are used to represent collections of users, machines, devices, and applications. Containers can be nested (created one-inside-the-other) to reflect accurately the company's organisational structure.
In this case, marketing and personnel organisation containers represent those respective departments, and their relationship to one another, within the company.

Grouping objects in the directory lets administrators manage objects on a macro-level (as collections) rather than one-by-one.
This increases management efficiency and accuracy while letting organisations align network management with their business processes.