Source: http://googleblog.blogspot.com/2011/02/update-to-google-social-search.html

Here's a link to the video included in the blog post in case anyone wants quick access and a brief explanation of the Google Social Search update:

http://www.youtube.com/watch?v=4hAgiIXuNbs&feature=player_embedded

Also

http://1.bp.blogspot.com/-Dn4ixEPG7nY/TVy9c9Zj9FI/AAAAAAAAHlY/k2pXOb9moEw/s1600/Picture%2B2.png

http://blogs.wsj.com/digits/2011/02/17/google-search-more-social/