Google Analytics had launched Universal Analytics last October aimed at enterprise users. Now this feature is available for all users. With Universal Analytics users can track both offline and online information.
You can read in detail in the Google Analytics blog about how to enable this features in your Google Analytics account. The process involves creating a new web property in your existing Google Analytics and then select the Universal Analytics column to get the new analytics.js code snippet you can implement on your website. You can select the feature as follows: