Tech

Interactive: See a visualisation of the links in your Facebook social network using this app developed by Touchgraph, a company based in New York

NOTHING personal, but I don't really want to be your online friend. I'm sorry, I'm sure you are very nice. It's not you, it's me: I'm feeling grumpy and a tad antisocial, so perhaps we are all better off.

And that goes for you too, annoying ex-classmate who just "friended" me on Facebook. Get lost, media-type I met at a party; your all-too-frequent status updates are pretentious. Trusted colleague, please stop judging my professionalism by the posts on my wall. And mother, you know I love you, but instead of getting upset, please just stop looking at my late-night pub photos.

It may come as no surprise that I have been having second thoughts about online social networking. Anecdotally at least, cutting the cord may be the healthy way to go. My wife shunned such networks from the start and yet has so far managed to avoid becoming a social pariah (between us, this has had an upside: up until now she has been blissfully unaware that an ex-girlfriend friended me last year). In short, what started out as a fun way to keep up with friends is now stressing me out.

For many of us - 400 million worldwide so far and counting - online networking has become enmeshed in our daily lives. It has transformed our social structures and behaviour. Research tracking our habits on these sites is only just emerging, and its conclusions have come as a surprise to cynics like me. It seems these tools are altering our influence over others, improving our chances of professional success and even making us happier. Could the benefits of social networking be too good to miss out on?

A decades-old insight from a study of traditional social networks illuminates one of the most important aspects of today's online social networking. In 1973, sociologist Mark Granovetter showed how the loose acquaintances, or "weak ties", in our social network punch far above their weight in their influence over our behaviour and choices (American Journal of Sociology, vol 78, p 1360). Granovetter found that a significant percentage of people get their jobs as a result of information provided by a weak tie. Subsequent studies have revealed that weak ties benefit our health and happiness. Granovetter suggested that this is because these friends-of-friends aren't like you, yet they are likely to be similar enough in social outlook and personal interests to have a positive influence.

Today, our number of weak-tie acquaintances has exploded via online social networking. "You couldn't maintain all of those weak ties on your own," says Jennifer Golbeck at the University of Maryland in College Park, who studies our use of social media. "Facebook gives you a way of cataloguing." The result? It's now significantly easier for the school friend you haven't seen in years to feed you a bit of information that changes your behaviour, from a recommendation of a low-cholesterol breakfast cereal to a party invite where you meet the love of your life.

The explosion of weak ties could have profound consequences for our social structures too, says Judith Donath of the Berkman Center for Internet and Society at Harvard University, who studies the various ways we communicate using social media. One thing that limited the size of traditional social groups was the time it took to form reliable and trustworthy ties, she says. Online tools have changed that, helping each of us to build a social "supernet": a network of easily accessible contacts that is bigger than any we have ever been able to manage. "It would be impossible to maintain 500 or 5000 ties without it," she says. "We're already seeing changes." For example, many people now turn to their social networks ahead of sources such as newspapers or television, because their acquaintances provide them with more trusted and relevant news, information or recommendations. However, Donath believes more should be done to maintain privacy and trust in the networking tools.

If these supernets continue to thrive and grow, they could fundamentally change the way we share information about the world and transform our notions of friendship and acquaintance. If so, says Donath, the likes of Facebook, LinkedIn and MySpace might just turn out to be the harbingers of a sea change in our social evolution, in the same way that the arrival of language transformed our ancestors (Journal of Computer-Mediated Communication, vol 13, p 231).

The magic number

But are these huge networks really that relevant to us on a personal level? Robin Dunbar, an evolutionary anthropologist at the University of Oxford, wrote the book How Many Friends Does One Person Need?. In it, he argues that our primate brains place a cap on the number of genuine social relationships we can actually maintain: roughly 150. We simply don't have the cognitive capacity or time for any more, he says.

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