Segment Generation information, only visible to users who initiated the segment generation.
Import (Auto and Manual) notifications for the whole account.
Corporate notifications, visible to all users.
To begin with, the Notification Center will only display important messages, which initially only include system-wide notifications. You can toggle this setting to include all notifications via the Only important switch at the bottom.
Messages are displayed in order of recency, with the newest at the top of the list.