Zipf Curves and Website Popularity
http://www.useit.com/alertbox/zipf.html

Nielsen, Jakob
Alertbox
1997

Abstract:

Much available data suggests that Web use follows a Zipf distribution. The figure shows the distribution of incoming page requests to www.sun.com during a one-month period last year. Each datapoint represents one page, with the x-axis showing pages sorted according to popularity: the first page is the most popular one (the home page), the second page is the one that received second-most requests that month, and so on until we reach page number 10,000 which was only requested a single time that month.