Of course, this is completely unsurprising to me, since we demonstrated it via datamining of MMORPG metrics five years ago. There’s some interesting stuff here about “core” or tight-cluster friends versus the extended network, however.

The rise of online social networks, with their troves of data, might shed some light on these matters. So The Economist asked Cameron Marlow, the “in-house sociologist” at Facebook, to crunch some numbers. Dr Marlow found that the average number of “friends” in a Facebook network is 120, consistent with Dr Dunbar’s hypothesis, and that women tend to have somewhat more than men. But the range is large, and some people have networks numbering more than 500, so the hypothesis cannot yet be regarded as proven.

What also struck Dr Marlow, however, was that the number of people on an individual’s friend list with whom he (or she) frequently interacts is remarkably small and stable. The more “active” or intimate the interaction, the smaller and more stable the group.

— The size of social networks | Primates on Facebook | The Economist.

As someone with a larger-than-normal extended network and a smaller-than-normal core network, I kind of live with this every day as I use social media. There’s a lot of talk about the issue of “unbalanced” followers/following number on Twitter, for example, or about whether social media are used as marketing tools by some folks. In my case, the answer is undoubtedly “yes,” though perhaps my style of personal marketing is fairly informal. At the same time, as I have commented to folks at the office, the first anonymous brown-paper-wrapped package you get at your home address, first death threat, first random fan phone call at dinner, completely changes your perspective on social media…