It's a small world and, according to today's prevailing common knowledge, with the help of internet based technologies, getting smaller every day. But how small is small? One of the more interesting questions that gets asked in that regard is how many clicks away any given web page is from any other page. The question has spawned a minor but substantial corner of the web all its own.
In a now famous experiment conducted in the 1960s, Stanley Milgram gave residents of Nebraska letters that were to be delivered to people in Massachusetts. His instructions were to give the letters to people whom they knew, who would then pass them on to someone they knew, until the letters reached their destinations. Milgram found that the average number of people that each letter "passed through" was six, thus giving the study the name by which it's best known: Six Degrees of Separation.
It turns out that at least some computer scientists aren't satisfied with the basic metaphor of six degrees, and have decided that they have to actually prove that it's a viable model for our lives. In 1998, for instance, two Cornell researchers, Steven Strogatz and Duncan Watts, published an article in Nature magazine entitled Collective dynamics of 'small-world' networks. Two years later, another Cornell mathematician, Jon Kleinberg, published an additional paper, suggesting a slightly different model for these networks, a model he called "the 'inverse square' structure". Using this model, messages would arrive at their destination more quickly because the general direction of their travel was already built in.
As interesting as the mathematical reasoning may be, I take a greater interest in the cultural expressions of the phenomenon. The best known of these seems to be Six Degrees of Kevin Bacon, the original site of which seems to have gone the way of thousands of others, though traces of it may still to be found in various corners of the web. Of course this site isn't the original. It traces its origins to an off-broadway stage play entitled (of course) Six Degrees of Separation which in turn took its central metaphor from the Milgram study. Six Degrees is a game in which we're invited to connect between Kevin Bacon and any other actor, with each link in the chain being represented by an actor who was in a film with the actor from the previous link. For a pleasant waste of time, one version of the game with a very substantial data base can be found here.
A game such as this doesn't require using the web. Though I've never tried, I'm quite sure that I can connect myself to Bill Clinton without needing more than six "clicks". Getting to George Bush might seem a bit more difficult, but considering that Clinton knows Bush, at the very most I only need one more click. It would also seem that there are a number of super-connected people who act as particularly potent nodes in these webs of acquantances. If you can link to one of them, you can very easily branch out it countless other directions. Still, knowing a particularly heavy node probably can't always do the trick. I have my doubts about needing only six clicks in order to get to someone I'm never heard of who lives in a rural settlement in China, for instance. On the other hand, I doubt that getting from anyone in Israel to anyone else in Israel would require the full six clicks - even without latching onto one of those nodes.
But even if I steer clear of the mathematics and stick to the metaphors, it doesn't stop there. A graduate student at Stanford, Lada Adamic, for instance, researches issues such as Friends and Neighbors on the Web, and The Small World Web. She explains that
The Internet has become a rich and large repository of information about individuals. The links and text on a user's homepage to the mailing lists the user subscribes to are reflections of social interactions a user has in the real world. We devise techniques to mine this information in order to predict relationships between individuals.and it turns out that this is the sort of stuff that search engines thrive on as they seek out better algorithms for finding just the right site we're looking for.
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