To determine the site traffic, number of people who visited your site and their geographic location, the page/s they visited, the amount of time they spent in browsing through your site, and other information that will be useful to keep track of what's happening in your site, use Google Analytics.
With the reports generated by Google Analytics (www.google.com/analytics/), you will be able to know what visitors do when they visit your site, what functionalities can be added to improve the visitor's browsing experience, and which marketing efforts are effective. This tool enables you to save time and money since it is free of charge and you do not have to track what your site visitors are doing - Google Analytics will do the work for you.