TUSILOG asks "What's with the Diameter?" in reaction to a recent Commentary on Visual Maps of the Filipino Blogosphere. There, mention was made of the DIAMETER of the blogosphere, prompting Tusilog's question.
I didn't mean to be mysterious and the answer is a well-established research result (see the title). I just wasn't sure a deeper discussion would be useful to anyone, but I did say to Tusilog in his Comments section that I would post a full report on this matter today. So maybe this will bring poetry, physics and mathematics all a lil closer together...here goes...
Round or spherical objects like the earth or basketballs have a characteristic size called their RADIUS, which the distance from the center to any point on the surface. Twice this distance is called the DIAMETER. Now if you think about it, you will realize that the diameter is really the MAXIMUM straightline distance between any two randomly selected points on the surface of the sphere or inside of it. So in that sense, the diameter is a measure of how big the thing is.
Now of course the visual representation of the blogosphere or the World Wide Web, which was the point of my original post, bears no resemblance to PHYSICAL balls or spheres since it is composed of billions of webpages interconnected in a highly complex manner, by weblinks. It does look like a web alright, up close, but zoomed out, it is more like a huge ball of yarn with millions of individual strings, knotted and intertwined together.
NO BLOG IS AN ISLAND: By definition, "every thing" is somehow connected to everything else in a network, because otherwise "the thing" is not part of the network. Of course, people travel from one point of the blogosphere (for example this webpage you are reading now) to another point of the blogosphere (another web page) by clicking on a series of hypertext hotspots called links. (which was the quintessential genius of Tim Berners Lee, inventor of WWW, but that's another subject...)
It is therefore a reasonable question to ask, given a randomly selected pair of points "on" or "in" the blogosphere, how many links must one click to traverse the distance between them. In other words, how big is the blogosphere, how far away from each other, using clicks as a measure of distance, can any two web pages be?
This is a very similar question asked about the human social network: If I want to contact a certain person Mr. X, how many degrees of acquaintance do I have to traverse before I find someone who actually knows him? The famous answer of course is SIX DEGREES.
So what is the Diameter of the Blogosphere? In the year 2000, it was "measured" to be around 19 "clickometers" wide! The definitive work on this question was done by a group of mathematical physicists at the University of Notre Dame led by Albert Laszlo Barabasi. They report their findings in the prestigious journal Nature, in a paper entitled, A. Albert, H. Jeong, and A.-L. Barabási, Diameter of the World Wide Web, Nature,401, 130-131 (1999).
It's not for the mathematically faint-of-heart, so I won't go into a discussion of the details of their work. People who are interested in this topic and the related one of POPULARITY on the world wide web should read up on the POWER-LAW DISTRIBUTION of Web audiences (20% of the websites control 80% of the clicks, or even more unequally, why?). Start here with Clay Shirky's classic, Power Laws, Weblogs and Inequality.
But I cannot resist including a beautiful rendition of the subset of the World Wide Web rendered by Barabasi et al as a result of the massive study that derived the 19-click diameter result. Here is what the Global Mind looked like in year 2000:
Each pinpoint is a website, and link density follows a pseudo color mapping where white is really intense.
Perhaps, if there is interest, I shall post some more on the even more important concern of bloggers: why the A-Listers seem to monopolize the trillion or so clicks available daily for ego-ramification.
(UPDATE: If you are really interested in the technical details, email me so I can send you a nice lil powerpoint that I downloaded years ago from Barabasi's website, but which I can't find on the Web any more. You can learn all about Poisson distributions, power laws, scale free network topologies, and lots of other sexy geek stuff...DJB)
(UPDATE 2: Next question is how big is the Filipino Blogosphere? In other words, given any two weblogs, say, whose owners would agree to be characterized as being part of the Filipino blogosphere, how many clickometers are they apart, how many links need to be traversed to get from one webpoint to another in the Filipino blogosphere?)