Once you have engaged visitors, you can begin to use social site features to amplify your messages by encouraging users to tell their friends by clicking a Like or +1 button, or by sending a message to their followers on Twitter. Amplification involves using the inherent strength of social networks. On Facebook, the average user has 120 “friends.” This includes all people they have ever friended, including people whom they don’t really know (and who don’t really know them). Facebook users typically have only three to four close friends with whom they can discuss confidential matters, and a larger set of around 20 friends with whom they have two-way communications (mutual friends). Let’s use 20 as a reasonable number of