The way the world works, you are either cool and have 600 Facebook friends, or you are worthless and only have 40. But it's not your fault. Science says it's genetic.
Well, more accurately, the study looked at the genetics of social interaction, particularly how people function in various social networks. What they found was that your popularity may be predeterminately hardwired into your brainbox. Science Daily summarizes a Harvard/UC study:
The researchers found that popularity, or the number of times an individual was named as a friend, and the likelihood that those friends know one another, were both strongly heritable. Additionally, location within the network, or the tendency to be at the center or on the edges of the group, was also genetically linked. However, the researchers were surprised to learn that the number of people named as a friend by an individual did not appear to be inherited.
So basically that means that if a bunch of people in a social network like you and recognize you as a friend, thus making you popular, it's because you were born that way. And if you are sad and lonely and existing on the outskirts of the Danville Community Players or the Amateur Dodgeball League you thought would be whimsical and fun but is actually just kinda depressing and the balls hurt, well... that was always in the cards for you. But there's nothing stopping you, genetically at least, from saying that people are your friends so you don't seem like the weird loner that you really are. Bright side!
And if you wanted to, as I did so recklessly above, turn this into some sort of Facebook analysis, you'd have to determine whether the person with 600 friends has received friend invites the majority of the time, or requested friends. Because the latter would just be a secret genetic loser. And those people need to be isolated (more than they already are, hah!) so we can eventually breed out the gene and then everyone will be popular. (Even though I think that's called Communism. Yay!)
The study also investigates how and why, in an evolutionary sense perhaps, various social networks work the way they do. Basically, all of it is is hinged on a shared will to survive, with risks and benefits regularly weighed against each other. Someone at the center of a network is more likely to be privy to news about a food source, but also more likely to contract a disease should an outbreak occur. A person who exists further out in the circle is safer from that illness, but further from the food source (or knowledge of said food source).
If you think about that in a modern sense—most of us, I hope, aren't actually physically huddled together looking for food and regularly falling prey to disease (this is America after all)—this explains why Stan and Judy never, like they have some weird aversion to it, never want you to hang out with their friend Claudia. People compartmentalize various friendships to keep certain things safe, to maintain different levels of distances. If Claudia and you ever hang out, some sort of "disease" could spread (most likely constantly-needling-Stan-about-his-job-itis). And that's not good for Stan and Judy. Minimizing your exposure to the damaging effects of other several-degrees-away social entities keeps you healthier—physically, emotionally, sexually, fiscally, whatever.
So don't feel bad that you never get to come along when your roommate goes out with her old Middlebury friends. It's only because you're diseased.