I want to mark some of my chat messages and/or notifications as unread after I read it?
Marking messages as unread after reading them
Go to your inbox, click on a message, click on "Actions" and then "Mark as unread"
Marking friend notifications as unread
There is no direct way to do this but until you have responded to a friend request (either accepted or declined), a count will be shown (like in the image below):
Marking notifications as unread
Again, I don't see a direct way of doing this. One work around would be to go to Settings > Notification Settings and turn on email notifications. You can mark the email as unread until you wish to do so!
Hope this helps!