If you would like to know who all have not responded to your friend request on Facebook yet, go to Accounts – > Edit Friends and select “Friends” unders Lists.
The status - Friend Request Pending - against any Facebook member in this list indicates that he or she is yet to approve (or ignore) your friend request. If you happen to visit any of these ‘pending’ profiles, their page will display the status as ‘Awaiting friend confirmation’ to you.
But that’s not all. If you ever invite non-Facebook users to become friends (say by importing your Gmail address book into Facebook), they’ll become your connection the moment they create an account on Facebook but not friends.
Go to Account – > Edit Friends and select “Invite Friends” from the right sidebar. Now click “View all Invites” and sort the list by “Joined.” What you see is a list of people who have accepted your invitation to join Facebook but may not have responded to your friend request yet.
Also see: Block all Facebook Apps & Games (Forever)