Mashable: Google's Social Search feature, first introduced in 2009, has just undergone a major upgrade. First, social results will now be integrated with the regular search results instead of grouped together at the bottom of the search results page. Second, Social Search now includes results from Quora, Flickr and Twitter. And finally, users now have more control and options regarding what appears in their Social Search results.
However, Google still doesn't integrate your Facebook friends' "likes" into its search results, although Microsoft's Bing does.