A rule is a setting customization that you make that determines a user's or a group of users' access to features when you want that access to be different from the default. For example, if you want only certain users to be able to create personalizations, your default setting for the option Enable the personalization tool would be disabled. By default, users cannot make personalization if the setting is disabled. Then, create a rule that can turn on Enable the personalization tool, that is, personalizations would be enabled for those users.