Is the list of friends on the left side of your Facebook profile random?

[Mia Johnson]

I've looked it up and apparently Facebook claims that the list consists of people you have the most public interactions with. I've also heard that it's made up of the ten people that view your profile the most. Personally, I think it's the latter, but might it also be partly people whose profiles YOU view the most? That would make the most sense to me, considering mine is made up of a few close friends (mutual profile viewing/interacting), one person I Facebook-creep daily (a profile I view a lot) and then a bunch of random others with whom I barely ever interact (people who view me a lot, possibly). In the case of the person that I creep daily, he shows up on my profile but I don't show up on his, so that's kind of weird.
If anyone has any information or theories or anything, please do let me know. I'm extremely curious, and I'm kind of hoping that it doesn't show the people whose profiles you check out the most and that it's just showing them because they happen to look at your profile a lot, too.

Thanks.