Depending on your configuration your Pages and Folders created in the 'Department' and 'Documents' wikitrees can be required to be revisioned in intervals. (If your configuration does not have this option, contact Colibo to change this setting).
The 'Required periodic revision' ensures that out-of-date Pages and Folders gets updated and unnecessary items can be deleted to prevent clutter. The changes is done by the users, nothing is changed or deleted by the system itself.
When the revision date is due the owner or editor who created the document gets a notification, reminding them to revise the page or delete it if it's not relevant.
When creating a Page or a Folder, the owner or editor can tick off the 'Required periodic revision' checkbox to enable the setting. The default period of revision is 180 days, but depending on the configuration of your intranet, this can be changed.