Six degrees of separation applies everywhere

One of the big surprises of the last five years of network research was that use is by no means limited to the society. But it's common in those networks. And it's common in the world wide web. My group actually looked at how far are webpages from each other. That is if you start from a certain webpage and you have a target webpage, how many clicks you have to do in order to get there on the shortest path. And the answer seems to be around 19. 19 may appear to be much longer than six, but you have to think about that you're talking about six billion webpages. And we claim that between any two webpages there is a link of about 19 degrees. Of course some of them are much shorter, and some of them a bit longer, but that is the average. But it's present in the cell as well. So you know, our body is made of cells, within every cell there is a very intricate chemical network, which tells us how the genes and the molecules interact with each other. Because genes only interact with specific genes, and molecules only interact with specific molecules. If you put all these interactions together, you get a very complicated network that is really the heart of life. And what you see is that in that network also any two molecules can be connected by a short path, or three or four. It's the same too on the internet. If you take any two computers on the internet, you would find a chain of wires that would connect them by four or five, six, seven, eight, nine, ten. It's not entirely clear what the number is. That many intermediate computers. So just about anywhere you look in society, technology, nature, where networks emerge, the small world phenomena is there and it's prevalent.