There are a ton of analytical engines and data capture for looking at your web visitors.  I use a couple here to look at the Apache logs as well as the actual activity of users using the site.  I can’t remember where I found it, but a beta system called Quantcast is doing some interesting demographic analysis of visitors.  Like many of the web analytics systems, you get some JavaScript to put on all your pages.  When a user – an actual living human, not a bot – interacts with the site, the JavaScript captures information and send it back to Quantcast.  Okay, so I only put this on DeepMarket a week or so ago, but it is fun to look at the demographics of my users so far – I made DeepMarket’s demographic profile public.  Wow – it looks like a lot of childless and rich people visit DeepMarket.  Hmmmmm…