The ShareThis module let you add a share button on any node type such that you can share the node content to Facebook, Twitter, Google Buzz or any other channels as shown in the following picture.

 

After you have downloaded and enabled the ShareThis module. You can configure its settings @ Administer –> Site configuration –> ShareThis.

 

As i have enabled the ShareThis button for Story node type, now you can share the any Story node to your friends.

 

Done =)

Reference: Drupal Module – ShareThis