Stay on Top of What Happens in Your Communities with Global Notifications
All events that trigger notifications (@mentions and group posts) are supported. Members can even trigger notifications on record feeds. For example, an internal member can trigger a notification from the Salesforce org by @mentioning an external member on a lead or opportunity. When a member clicks a notification, the originating detail page or other appropriate location is displayed for seamless collaboration across communities and apps.
By default, the Notifications icon is hidden in existing communities and displayed in new communities. For the default Customer Service theme layout, show or hide Notifications for your members by selecting Hide Notifications icon in community header inin Community Builder.