Social gadgets
Social gadgets let you share information and play games with friends. You can tell if a gadget is social if it has the icon in the top right corner. Click the icon to see the gadget's social settings. The figures in the icon will show up inside a border when social options are enabled. To share social gadgets with your friends, use the drop-down arrow and click 'Share this gadget.' Learn more.
Source: http://www.google.com/intl/en_us/help/ig/social/We've added some features to your iGoogle homepage that will enable you to post updates and play games with friends: http://www.google.com/igsocial