In order for you to start using Social Search you first have to go to Google Labs experimental section and then activate the Social Search Feature. Social Search will only be available in US and English for now.

From what networks?

Social Search will tap into three different sources, so you will need at least one of these accounts to make Social Search work, I would say at least Google profile would be best, if you don’t have one go make one here.

Social Search uses your Gmail’s contacts that you have created with your friends and coworkers for email and chatting with Google Talk. Social Search also uses your Google Reader subscriptions and all the social networking profiles that you have linked into your Google Profile.

Now you don’t need a Google Profile, this is the place with all your social networking profiles for Social Search to gather information from friends. Based on the information you give in your Google Profile, Google can now auto-detect all of your social networking profiles and your friends connected to services like Facebook, Flikr, FriendFeed, YouTube, Reddit, Digg, BrightKite, and  so many others.

How it Works.

Once you have activated Social Search, It’s results will appear at the bottom of your stand search results page and will be clearly labeled as “results from people in your social circle.” Goggles search evangelist Matt Cutts pointed out is that it is important to note that not every search will trigger the Social Search results. Now when it does, the  search results should be highly relevant to your search query .

You may also manually trigger Social Search from your search options panel while you are logged in. There, Google will now present a list of all your friends that it thinks that are closely relevant to the key phrases you were searching for.  By clicking on a name you can restrict your results even further and see results from just one person or two people.