This is a HotDoodle Patent Pending Feature -- you can give each new registered user their own pages to edit!
Upon registration, a page and all of the sub-pages under it can be copied and renamed. At the same time, the rights of an example user can be copied to the new user. If the example user had editing permissions in the copied pages then the new user has the equivalent editing permissions in the new pages.
The permissions do not have to be entire page edit. For example, maybe the pages being copied are member profile pages that allow the new user permission to add pictures and change text but not permissions to add blocks or sub-pages. You can set it however you wish.
Other permissions are also copied. For example, if the "copy rights of" user had permission to participate in a discussion board, then the new user will also have such permissions. Generally, however, other permisisons are best handled by granting them to groups and causing the new user to be members of those groups by means of having the "copy rights of" be members of those groups.