It's necessary to understand visitor behavior: You should monitor the number of visitors and where they come from, understand how they navigate your site and what keywords they like, or get a feel of whether your site is meaty enough to hold their attention.

I use Google Analytics anf Hit Tail to measure and track visitors.

Google Analytics is a software that offers an end-to-end website metrics and that too in a readable format. You can have executive summaries of e-commerce, traffic, and conversion trends through this software, without looking for the same anywhere else. You can find out how your visitors found your site and how they interact with it. This software has been designed to track all kinds of online campaigns. This includes everything, starting from emails to keywords, irrespective of the search engine or the referral source used. This analysis helps you improve your site and generate more traffic. The most tempting part of this software is that it is for free, with a tag of "Google". It is a great combination that is hard to ignore.

For more detail and to join follow this URL http://www.google.com/analytics/

HitTail reveals in real-time the least utilized, most promising keywords hidden in the Long Tail of your natural search results. They present these terms to you as writing suggestions that, when used as the topic of new site content or blog posts, can boost the natural search results of your site. It's that simple.

For more detail and to join follow this URL http://www.hittail.com/