This is one of the most popular plugins you can find on wordpress and will allow you to track user behavior on your website so you have a better idea of what your site visitors are looking for when they visit your site.
Using analytics on your website is essential if you want to optimize your website and its content. By having access to the data you can quickly and easily identify any trends and adapt accordingly your site.
Best of all, this wordpress plugin is 100% free. Enjoy!