The top 3 statistics and tracking programs that I've seen users implement are:
Sitemeter - a service which provides counter and tracking information for Web sites. By logging IP addresses and using JavaScript or HTML to track visitor information, Site Meter provides Web site owners with information about their visitors, including how they reached the site, the date and time of their visit, and more. http://www.sitemeter.com/
Google Analytics - a free service offered by Google that generates detailed statistics about the visitors to a website. Its main highlight is that the product is aimed at marketers as opposed to webmasters and technologists from which the industry of web analytics originally grew. http://analytics.google.com/
StatCounter - A free yet reliable invisible web tracker, highly configurable hit counter and real-time detailed web stats. Insert a simple piece of our code on your web page or blog and you will be able to analyse and monitor all the visitors to your website in real-time! http://www.statcounter.com/
Descriptions from Wikipedia & Statcounter
Which add-ons / plugins / or programs do you use? What features are important to you in a statistics program? Do you use something else? What would you suggest?







