Get a Google Analytics Account
Sign up for a Google account if you don't already have one and set up Google Analytics.
Its very easy to instal the tracking code - if you have a dynamic scripting language bring it in through an include file. This makes changing the code or updating it easier in the long run.
It gives you very valuable data and can help you to improve your site. Google Analytics takes into account user behaviour data and modifies rankings based on how people use your site. If your site is well designed and usable it will rank higher. If it doens't Google Anlytics will show you this and you will know where you need to make improvements to your site.
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Sign up for a Google Analytics Account and find out how people use your web site.