According to Cameron Marlow, Facebook’s “in-house sociologist,” that number is four if you are male and six if you are female. As the Economist reports this morning, Marlow’s research indicates that the average Facebook user has a network of about 120 friends, but only has two-way conversations with a very small subset of these ‘friends.’ Interestingly, even for those users who have a far larger number of friends (500+), those numbers barely grow (ten for men and sixteen for women).
Those numbers cited above are for friends that users actually email or chat with. When it comes to more casual one-way interactions like leaving comments on photos, status updates, or writing on somebody’s wall, those numbers increase slightly and the average male would then have seven friends on Facebook and the average female about ten.
Based on this data, Marlow argues that once your network grows beyond the Dunbar number of 150 (the theoretical cognitive limit of how many people one can maintain a stable social relationship with), you are, at best, increasing the number of ‘casual contacts’ that you track passively.
What About Twitter?
Marlow, of course, focuses only on Facebook, but these numbers are also quite interesting in the context of other social services like Twitter. Just this week, we saw a an interesting discussion about how many followers one can really interact with on Twitter – especially considering that some users there follow tens of thousands of people.
While some of these numbers for Facebook probably also hold true for Twitter, it also needs to be acknowledged that Twitter is a far more casual network than Facebook, where users just dip in and out of the message stream during the day. Also, the concept of ‘friendship’ in general also seems to be more loosely defined on Twitter.
But if you really wanted to have a two-way communication with most or your Twitter followers, then following 10,000 people is simply crazy. However, those Twitter addicts who follow this many users probably also only really track a very small subset of their followers through groups on Tweetdeck and searches.
