Google Analytics is a free service that can provide you with a wealth of information about traffic to your website. For example:
To add Google Analytics to your site, first create an account at google.com/analytics. You will be provided with a "property ID" and a tracking code. You can ignore the full tracking code - all you need is the Tracking ID:
Paste the ID into the space provided in Pianola and click Save. Pianola will now start sending detailed information to Google Analytics automatically.
Pianola uses the latest version of the Google Analytics Tracking Script, known as Universal Analytics. This will give you access to all the latest features offered by Google.