There’s an area of Facebook that I believe really needs to be addressed for a variety of reasons. As you begin finding old friends from high school, connecting with extended family members as they begin using Facebook, and maybe even start connecting with clients and co-workers, there’s an issue of who gets notified of your updates when you have them.
If you imagine all the different groups of your contacts as an extending circle of influence similar to what would be shown in the image below.
Let’s think about your closest friends or family being the center circle, and extend from there the groups of people you have less contact or influence with in your personal life.
You may want to send an update to your friends and family, that’s not seen or available to your old high school friends, or perhaps more importantly those clients and co-workers that you’ve found on 
Facebook.
As far as I know, there’s no way to accomplish this currently on 
Facebook. In some instances your circles may not nicely overlap.
It’s this occasion where I think you should have the ability uncheck different groups of your friends to not be informed of an update or be able to see it as visible. By default all of your updates would go to everyone as the functionality exists now.
But on those occasions where you would like to exclude certain groups, you could uncheck their group for being included in the update. Also, if an update was marked private in one of these instances, any response by that group of friends would also only be viewable by the people you’ve identified as being able to see that update. So someone’s response to your “private” update should not appear on their wall.