This is how Facebook knows who your top 9 friends are

This is how Facebook works out who your top 9 friends are (Photo Courtesy)

Like MySpace before it, Facebook seems very keen to rank your friends in order of who you see on your profile.

The social networks algorithm for displaying your top nine buddies in that grid on the left hand side has been the subject of an interesting piece over on Motherboard .

Why, for example, do people you haven't interacted with since school frequently appear on your list.

Is it because they've been checking up on you?

Facebook told Motherboard that the people you see in your grid are a "group of relevant friends intended to be a useful prompt."

Because Facebook's advertising-based business model works best when you're interacting with as many people as possible, the algorithm behind the scenes works to push this.

Therefore, if you've been 'friends' with someone for a long time, but haven't spoken to them, it would be really useful for Facebook if you guys struck up a conversation again.

It's also tied in to mutual friends and mutual interests. The social network also confirmed that it's algorithm is ever-evolving.

"It uses machine learning and takes thousands of data points into account to determine people’s social proximity," writes Motherboard.

"But assuming the basic tenets are the same, the equation likely weighs various types of interactions differently: Being tagged with someone in a photo or attending the same event is a better indicator that you’re tight with them than liking a news story they shared or commenting on a wall post."

Of course, just to mix it up a little bit - Facebook also said that the occasional appearance by a vague contact is purely random.

Researchers from the Happiness Research Institute believe that Facebook users are constantly being given an artificial impression that others are happier than they are on the social networking site.

The Denmark-based institute carried out an experiment on 1,095 people who gave an average ranking of their current state of happiness as 7.6 out of ten.

Half of the users were told to stop using Facebook, while the other half were told to continue using the site.

One week later, those who had not logged into Facebook had their happiness boosted to 8.12 out of ten.