Google Analytics
The Google Analytic tool is one that I highly recommend to my affiliates. This is a website tracking system provided by Google that shows everything in full detail such as where your visitors are coming from, how many visitors you have, and much more. Knowing this information can help you to identify important geographic information in order to cater your website to your customers. It can also tell you the busiest times of traffic or slowest times visitors come to your site. One of the best features is its ability to tell you the sites for where your traffic came through, giving you an opportunity to advertise to your target market.
The Google Analytics program is a free service of Google. You can find the registration link at www.google.com/analytics.