Read original post at Mikael Koskinen's Blog
Both the Windows Phone and Windows 8 apps have live tiles which can be controlled by the developer. But where the Windows Phone tiles have the front and back sides, Windows 8 tiles have a notification queue. Live tile’s notification queue can be used to show multiple different messages to the user, like the latest news items or recent emails.
Here’s some example code which shows how to use the notification queue in a Windows 8 Metro app and how to update the queue periodically using a ASP.NET Web Api backend.