World Wide Web scaling exponent from Simon's 1955 model

The statistical properties of the World Wide Web have attracted considerable attention recently since selfsimilar regimes were first observed in the scaling of its link structure. One characteristic quantity is the number of (in-)links k that point to a particular web page. Its probability distribution P (k) shows a pronounced power-law scaling P (k) similar to k-gamma that is not readily explained by standard random graph theory. Here, we recall a simple and elegant model for scaling phenomena in general copy- and growth-processes as proposed by Simon in 1955. When combined with an experimental measurement of network growth in the World Wide Web, this classical model is able to model the in-link dynamics and predicts the scaling exponent gamma =2.1 in accordance with observation.