• If you check this box, all of the sub-pages will have a light-bulb icon on the title line. If you click this icon, it will turn the light on () or off (). "On" means that everybody can see the sub-page, and "off" means that only you and the creator of the sub-page can see it. The default is off. This means that people with adder rights can tack pages onto yours, but nobody can see such pages until you explicitly turn them on for everybody else.
• Note that if you uncheck this box, and then at some later date come back and recheck it, the on/off status of all of the sub-pages will be restored. But this does not mean that the mechanism was in effect the whole time — it just means that the status was saved, even though the functionality was disabled.