Hi,
My boss asked me if Weblog expert (http://www.weblogexpert.com/lite.htm) is reliable in calculating the average time of the incoming visitors in a web site. Since HTTP is a stateless protocol, I think that the average time might be something left to personal interpretation. Does any one uses Weblog Expert? Is the visitor's average time reliable? Does anyone understand its criteria about how it process Apache logs to understand the average time?
I can't comment on that site in particular, but average time is usually calculated using some very clever bits of javascript.
You can set events on various parts of the page in javascript which fire off requests to servers. For example, when the user navigates away from a page or clicks on a link or closes the window the browser can send off a javascript request to their servers letting them know that the user has left. While this isn't 100% reliable, I think it provides a reasonable estimate for how long people spend there.