With many of the settings for the various Joomla Components you may see a Shared Options or Shared Layout Options tab.

Shared Options refers to parameters that are shared by several Components.

Examples of Shared Options:

Article Manager Options: Shared Options has options for setting parameters that would apply to Single Article, Category Blog and Category List displays. These are things such as the order of Categories and Articles, what parameter sets the date for ordering and pagination.

Tags Configuration: The Shared Layout Option tab allows you to control parameters that are common to all tag layouts.