Website efficiency and effectiveness

CodeTron (Rob) commented on one of my posts. I looked at Rob's blog and that reminded me of something I did a while ago. He was analysing the Google page-rank and mentioned the probablity of being on a web-page.
I ran an internal website for a couple of years and wanted an efficient and effective design. There are many programs that will analyse your web statistics, but few that tell you how to improve your site.
Running our website we wanted to provide information quickly and efficiently and I used one simple measure; for each page I counted how many pages were viewed before getting to the current page.
The number of web pages viewed is a stopping probability and followed a geometric distribution; the probability of stopping gives a measure of how good you web-site is at providing information. The higher the probability of someone leaving, the better the site is at providing information. i.e. The user found the information quickly and left.
Re- reading that (25OCT07) I need to explain. Assuming the site is an information site or product catalogue you want the person to find what they are looking for as quickly as possible and you do that by having found whate they want in as few clicks as possible, i.e. they found what they wanted in the minumum number of clicks and left the site. Most analysis programs count the number of pages viewed per hour/day/whatever and you want that number to be increasing. There are a few ways of doing that, increasing the number of visitors, increasing the number of visits, increasing the number of pages viewed per visit.
Assuming they left on the page they were looking for , then I moved the pages that were most frequently stopped higher up the hierachy (search).
By moving the pages I effectively increased the probability of finding the answer. Within a month I had doubled the probability of finding the required page (as measured by the slope of the geometric distribution). At the same time the number of hits increased dramatically. As the site became more useful, it was used more frequently. I had more visits that viewed fewer pages but my overall traffic (visitors per day) increased substantially.