Facebook Timeline's Top 6 Friends
Before we start, take a look at your "Top-6-Friends" display on your own Facebook Timeline.
Odd, isn't it?
Of the 15 people who constantly show up interchangeably on my Facebook timeline display, I have not interacted with eight of them for at least the last six months.
Which means that either I stalk their Facebook profiles regularly, or they stalk mine.
What an odd algorithm.
(This is just my speculation, though...)