This document discusses building a social networking site using open source tools. It lists required functionality for social networking sites like profiles, status updates, friends lists, and messaging. Reasons for building your own site rather than using existing ones are discussed, like having more control and the ability to innovate. Popular open source platforms for building social sites are mentioned, including Drupal and WordPress. Specific Drupal modules are listed that provide functionality like user groups, Facebook integration, and activity streams.