Google introduced Social Search back in 2009 where you find more relevant information from your friends through social networks such as Facebook and Twitter. This was available only on English speaking countries but as of last week it's now available to all countries. For example, if you’re looking for information about hotel and one of your friends has written a blog post about it, that post may show up higher in your results with a clear annotation and picture of your friend.

In more detail: 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. You can see a complete list of the people included in your social search results in your personal Google Dashboard (this display is private). For an overview of Google Social Search, check out the explanatory videoYou can watch the full video: Social Search