Google is currently introducing a Facebook liked new social networking feature called Google Buzz to their GMail users by phase.
If Google Buzz is already made available to your GMail account, you will see a new menu option named as "Buzz" right below "Inbox" of your GMail menu option list.
You can also access Google Buzz with your smart phone. The interface will be pretty much Twitter liked. The Buzz mobile application is currently available for Android, iPhone, etc. Just visit to buzz.google.com in your phone's browser to install it.
Similar to Facebook and Twitter, you can post a short update about what you are doing or thinking in Buzz, and share it to your selected group of people.
When you see an update from your friend, you can make instant comment on them, which will appear on the Buzz screen of everyone else within the social circle.
You can also showcase and share videos, photos and Web links to interesting stories.
Here is a video introducing the features available in Google Buzz.
Click here to learn more about Google Buzz.