Windows 8 Start menu is full of tile which keep on updating with the notifications as they find something new. Now the problem here is that apart from anything new, some of the tiles might be displaying even the older notifications along with new, the next day or even after you had restarted your PC.
I am guessing that there is an API for the apps to clear those old notifications but for users there is a permanent option that can be used for all the tiles. You should be a System Admin to make these settings.
- Go to Run Prompt and type in GPEDIT.MSC
- Navigate to User Configuration > Administrative Template > Start Menu and Taskbar
- Enable option for Clear History of Tile Notifications on Exit.
This will make sure that when you either log out or restart your computer, the older notifications for all the apps are gone.
There is an obvious drawback or problem with this, that even if you have seen it but did not notice it, the notifications will be gone. I don’t there is anyway for Windows to find out if you have read the notification because it is displayed and expected that you might have seen it.
I really wish there was individual control i.e. per app basis and could have been configured by just doing a right click on any of the app. Hopefully if there is an API, the apps will be implementing this as a configurable option.