The bigger it is, the more you have.  Puns aside, a study concluded with a correlation between the mass of your brain size and the amount of Facebook friends you have. 

In the time people have argued between Facebook and Google+, Researchers at the University College of London donned the white coats and spectacles to investigate whether having a hissy fit over the Internet being bad for humans is really necessary.  To do this, they took brain scans from 125 students, who are active on Facebook, and compared their brains to the size of the students' network of friends.  They found that the grey matter in students with masses of Facebook friends (who they probably don't even talk to) is larger than those with fewer.

By Grey matter, we mean the amygdala: the region associated with memory and emotional responses.  This was larger in the friendlier and more 'social' of Facebook users.

The scientists don’t know whether the larger brain regions are a result of having more friends, or if that particular gray matter might somehow facilitate having more friends, making friend hoarders hard wired to be more social. Personally I’d much rather assume it’s the former. I hate hard wiring! Change is good.

“The exciting question now is whether these structures change over time—this will help us answer the question of whether the internet is changing our brains.” Ryota Kanai, author of the study, commented.

The study has been published in today's issue of the Proceedings of the Royal Society B.