Measure the value of social media with
Google Analytics
A new set of Social reports help you measure the impact of your social marketing initiatives and evaluate the effect social media has on your Goals and Ecommerce activities. The 4 new reports aggregate key data points to help you see the complete picture of how social marketing and media affect your business. You'll find the Social Value Overview, Social Sources, Social Plugins, and Conversion Reports in the Traffic Sources section of your account.
http://support.google.com/analytics/...nt=Social_text