If you are interested in tracking activity on your system you can do it with Google Analytics. Its free and gives you a plethora of info to look at, such as where your users are, how long they spend on your site, which page they look at the most etc
Add your Google Analytics ID on the System Settings > Appearance page.
Google Analytics works on all pages of the client side. You can also enable Ecommerce Tracking (in Google Analytics), allowing you to see all your web data in conjunction with data about orders (product, price, tax, shipping costs etc)
Some screenshots of the Google Analytics dashboard with Ecommerce enabled: