<< Social search results are only visible to you and only appear when you choose to log in to your Google Account. If you’re signed in, Google makes a best guess about whose public content you may want to see in your results, including people from your Google chat buddy list, your Google Contacts, the people you're following in Google Reader and Buzz, and the networks you’ve linked from your Google profile or Google Account. For public networks like Twitter, Google finds your friends and sees who they’re publicly connected to as well...

Social Search is rolling out globally in 19 languages and should be available in the coming week, with more languages on the way. People around the world will find similar types of social results as people in the U.S., and we plan to introduce the +1 feature as soon as we can. With these changes, we want to help you find the most relevant information from the people who matter to you. >>

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

http://googlesocialweb.blogspot.com/2011/05/social-search-goes-global.html