Event Tracking is one of the most powerful tracking possibilities in Google Analytics to track the virality of what you produce on your website, blog or web project. With even tracking you can simulate page views in flash files so that you can see the interactivity between your user and your flash file. With Event Tracking you can track clicks on buttons, how long it takes to load a certain element, or as in this example how many people shares your material on social platforms/subscribe to your RSS.
The implementation requires that you have an account on Google Analytics and that you have implemented the ga.js script instead of the legacy urchin.js script in the bottom of your pages.
Here is an extremely helpful tool I have completely missed out on so far in Google Analytics. Annotations is one of those things that makes your stats understandable and shareable within your organization. We cannot see similar functionality in other tools out there and Google are currently really pushing to become the number one in Analytics online.