Is Facebook’s graph theory algorithm working fine?

I’m not sure how many of you have noticed this but there are days when your count of friends on Facebook fluctuates up and down. Not by much, mind you… maybe 1 or 2, sometimes even 3. And I’d be wrong to say that it fluctuates up and down… it usually goes down, then comes back up to the correct level. It never exceeds what the true count is.

But the question here is why?

Why does the count of Facebook friends change?

What is it that makes Facebook drop off a couple of friends from your list… and then bring them back up?

Initially, I thought it was because maybe some people have unfriended me – but then when the count came back up to normal, I realized that hadn’t been the case, since I hadn’t added anyone back.

Maybe it’s got to do with the algorithm they use – but if it’s an algorithm that’s supposed to work for 700+ million users, shouldn’t it be dead accurate?

And if it isn’t the algorithm, then it’s probably something else.

Guess we won’t know what’s wrong till Facebook fixes it (and lets the world know too), assuming they know about this problem already.