Global social networking just doesn't seem to mean anything

Over at Mashable, Peter Cashmore tells us that Mixi has become the largest social network in Japan. We've already seen the scale of CyWorld in South Korea, the rise of Bebo in the UK (to the point where it has overtaken MySpace and allegedly declined an offer of £300 million from BT) - now Japan's own homegrown social network becomes the biggest in its domestic market. This as MySpace becomes - by certain measures (BloggingStocks) - the most visited site in the world (eConsultancy).

We know that networks thrive on size. eBay does so well because it is a market and the size of its network of buyers and sellers creates a virtuous circle. MySpace is a network too, of course, and its scale is its virtue - if all your friends are on MySpace, that's where you socialise online.

It's in the details of "all your friends" that the rub lies. Steve Yelvington was riffing a few weeks ago on the Dunbar Number - anthropologist Robin Dunbar's groundbreaking revelation that the human brain is hardwired to "know" a maximum of 150 people and that 150 is therefore the upper limit of anyone's network of intimates (see a link to Dunbar's brilliant book in the sidebar of this blog, if you want a copy).

What this means, I think, is that it doesn't help MySpace to grow in Japan that it has millions of US users. It doesn't help CyWorld grow in America that most Korean teenagers of a certain age use CyWorld. It certainly doesn't bother me that MySpace is bigger than LiveJournal, because the fewer-than-150 people I know in the world who use a social networking site use LiveJournal, and it wouldn't be helpful for me to have hypothetical virtual access to millions of American teenagers when I barely have time to keep up with the people I do know. Hence Mixi storming Japan. If each Japanese social networker finds the 150 people they actually want to keep in touch with on there rather than MySpace - the extra 100 million people on MySpace just aren't relevant.