Facebook has completed quite a significant chunk of data mining and believes that the social network has cut the 'six degrees of separation' theory down to just four.

For those who aren't au fait with Six Degrees Of Separation it's a Will Smith movie, but that's not important right now – what is important is that Facebook believes that you may now be linked to a random stranger in just four degrees (five hops) rather than the much-debated six.

Separation game

"Using state-of-the-art algorithms developed at the Laboratory for Web Algorithmics of the Università degli Studi di Milano, we were able to approximate the number of hops between all pairs of individuals on Facebook," explained the Facebook data team in a blog.

"We found that six degrees actually overstates the number of links between typical pairs of users: While 99.6 per cent of all pairs of users are connected by paths with 5 degrees (6 hops), 92 per cent are connected by only four degrees (5 hops).

"And as Facebook has grown over the years, representing an ever larger fraction of the global population, it has become steadily more connected. The average distance in 2008 was 5.28 hops, while now it is 4.74."

To back up Facebook's theory, the blog links to two studies that show that we are now all linked by just four degrees of separation.

Rumour has it MySpace is trying to outdo Facebook with its 'three degrees theory', which involves playing the song 'When Will I See You Again' on its site on loop.