(Murdoch Fumes as Facebook Overtakes MySpace)
Perhaps this should be marked as a cross-over point in market structure reminiscent of the "serial monopoly" or "serial oligopoly" that often observed in emerging marketplaces where network effects provide significant value to the network users. Think of instant messaging, search marketing; or for older readers, PC-based word processing or spreadsheet software.
Or maybe its just that online social networks are starting to mirror social networks in that other, real, world. They may eventually consist of a small durable and evolving core of networks (plural) surrounded by a busy swirl of transitory, largely inconsequential interactions whose importance and permanence diminish quickly with distance and time.
Note that I wrote, "...small, durable core of networks". In the real world, most people maintain multiple, distinct social networks. And these may be overlapping or mutually exclusive or something in between. For example, colleagues at a new job vs. college drinking buddies. Facebook and MySpace both operate on the dubious assumption that what I'm willing to share with my college drinking buddies should also be shared with prospective employers, my local pastor and Aunt Millie.
Also, social networks in the real world rarely grow indefinitely and infinitely large. Maintaining relationships in the real world requires an expenditure of effort, which puts an upper limit on effective network size. As we move through the paces of our lives, we often prune the outer, less intimate branches of our social networks. On the internet, it's easy to "add a friend" and the maintenance costs (a little storage at pennies per gigabyte) are low and getting lower. But there is almost certainly an inverse relationship between the value of (personal) information shared on a social network and the size of the audience, which ultimately is a negative network effect. And sometimes it's even more important to prune the most intimate branches of one's social network... that's why ex-boyfriends and girlfriends are rarely invited to weddings.
Before a winner is declared in the social networking arena, a great deal of evolution in the product offering (and of course the business model) will likely occur, and it's probably way, way too early to declare one of the today's leaders the inevitable champion. Also, keep in mind that any discussion of MySpace vs. Facebook will probably sound parochial to tens of millions of social networkers in China.
Many, if not most, observers thought "Internet Search" was over after Yahoo emerged as the dominant portal versus its contemporary challengers -- Excite, Lycos, InfoSeek and AltaVista -- while Google's founders were still working on their doctorates.
In five years, a debate about the dominance of Facebook vs. MySpace may be as quaint as a discussion today about whether Yahoo's home page index of the web was preferable to AltaVista's search engine or whether Multimate or WordPro was the best PC word processing software in 1985.
Updates
2009-12-17 - The Financial Times has a nice epilogue on MySpace
2010-10-17 The NYT has a nice article about dual profiles on Facebook. I love the irony of friends emailing each other (that's so 2005!) to get permission to post vacation photos on Facebook.
