This module allows users to either get notifications when a node hasn't been updated in x amount of time, to automatically unpublish such "expired" nodes, and/or to receive e-mail notifications and unpublish x days afterward.
Additional settings include allowing inheritance of the expiration settings from a book page to its children, renotifications (Notify user every x days before unpublishing), an email carbon copy address, and customizable email content. One can also choose specific node types that the expiration settings are allowed to be set on, as well as what defaults should be used for them.
In conjunction with book inheritance, an admin may decide who can and can't edit the expiration times while the parent book settings are still inherited.
If the admin sets the automatic unpublishing to anything but "Immediate", an additional page is available to view expired modules. ?q=admin/content/node/outdated
This module requires the use of Drupal's cron system for automatic unpublishing and email notification features.