While difficult to grasp at first, this mechanism provides unprecedented power once understood. Of course, a subfolder receives not only the direct children of its parents, but the transparently inherited children of its parents as well. Thus a folder three levels deep has direct access to the children of its parents' parent. This technology is called acquisition. For example, when you're at home your telephone number is acquired from your house, and when you're at work your telephone number is acquired from your office.
Acquisition can be very practical in an object system that models a web site.
For instance, group of pages should have a consistent headers and footers, but pages in certain directories should override these defaults, and in doing so new defaults will be set for their own children. Another excellent example is Zope's security model. When you set the access permissions for an object, all of its subobjects will be subject to the same security restrictions by default. These restrictions are cummulative, so subobjects may further tighten security, but may not relax it. Even as you write a simple HTML page through the Zope interface, without knowing it, you're creating an object.