On Wed, Sep 10, 2003 at 10:12:11AM -0700, Carl Witty wrote:
On Wed, 2003-09-10 at 05:44, Jimmy Wales wrote:
Anyhow, my research at the time suggested that for every *doubling* of traffic, you generally *halve* your rank. That's a rough rule of thumb, but it held remarkably well.
That is, a site ranked 500 has twice the traffic of a site ranked 1000. And a site ranked 845 has twice the traffic of a site ranked 1690. If we are 2,140 and they are 845, then they have more than twice the traffic that we have.
Actually, I read somewhere that this seems to be a general law for all kinds of rankings. That is, if you rank cities in the United States (or the world) by population, a city with twice the rank will have about half the population. If you rank English words by frequency of usage, then a word with twice the rank will be used about half as often. (And of course there's nothing special about "doubling"; something with a rank ten times as high will have one-tenth the popularity.)
Yes, this is known in statistics as the Yule distribution. The observation that the Yule distribution holds for English words is known as Zipf's law. The fact that this holds for websites also seems to be well known, in the context of weblogs - http://www.shirky.com/writings/powerlaw_weblog.html ("Power Laws, Weblogs, and Inequality" by Clay Shriky.) The law is a simple consequence of modeling a web surfer as a random monkey (clicks on a random link on the current web page, after a while gets bored and goes to a random web page), which is also the same model used by google to calculate pagerank.
Arvind