When posting a new status message on Facebook, it displays a lock icon with a downward pointing triangle next to the Share button. Clicking on it brings up a menu that allows you to make that status available for everyone to view, restrict it to your friends of friends, or to just your own friends.
If you click on the Customize option, it brings up the window displayed above. Here, you can make your status visible to specific people or to all the people on one or more of your friends lists. Alternatively, you can go in the opposite direction and restrict certain of your friends from viewing that status.
On a social network like Facebook, where you are simultaneously friends with not just your real life buddies but also friends made online, acquaintances, family members, and colleagues from work, this feature gives you powerful ways to filter your posts for just the people you want.