At the end of January 2010, Google launched Social Search. To access that option, click Show Options, then click Social. Here’s a demo on YouTube: http://www.youtube.com/watch?v=aYf5iSA6t6g
Basically your Google Social Search results are customized for you based on your Google Profile. Add people to your Social Circle in order to personalize your social content. To set up your profile, go to http://www.google.com/profiles.