In order to work with Google Analytics you need to have an account with Google and to have registered an Analytics Account. You can pass the UA you get from Google to the GoogleAnalyticsUA property of the RadSocialShare. Please keep in mind that the statistics are updated every 24 hours and not in realtime.
Google have limited the browsers they support only to the latest versions and will, therefore, not work in older browsers such as Firefox 3.5, Internet Explorer 7 and Safari 3. More information on the matter is available in their official blog: Google browser support