You may have noticed that the same friends often pop up on your Facebook profile under the “Friends” section. You may have also noticed that these friends are ones you're interacting with or “know” the most. This is no accident.
Facebook “ranks” your friends on a basis of your interactions and connections with them, from mutual friends, relationship status, messages sent and profile visits.
This is all in an attempt to make your Facebook experience one involving your closest of thousands of friends, as opposed to random people from your high school or college classes that you don’t want to necessarily interact with.
There have been a variety of tools that claim to rank your Facebook friends, but the one created by Arjun Sreedharan seems to be the easiest to use and most comprehensive so far.
In order to find your "closest" Facebook friends, all you have to do is drag this link into your bookmark bar, log in to Facebook and click on the bookmark.
This will bring you a list of names of your Facebook friends, with the top being the most important to you (in theory) and the bottom being the least important, or least interactive. The lower the number next to the person’s name, the higher the rank.
Test it out! You may interact with certain people on Facebook more than you realize.