I have installed the User Tagging plugin, which allows you to mention users by the old Twitter formula @username. Any user so tagged will get a notification, ensuring that important posts will reach the people that need to read them. I recommend mentioning the @username tags in small print at the bottom of the respective post as otherwise it could become disruptive to reading flow. You can also tag entire threads with users while creating them, which might be useful for meeting threads, but is not recommended for news threads.
Enjoy.
Enjoy.