Social Networking

http://elgg.org, http://community.elgg.org, http://elgg.org/about.php

Drupal, http://drupalsn.com

Socialtext

Social Networking - For a major social network choose elgg. However, if you are looking to build a more niche/smaller social network then Drupal is perfect. Again referencing to it’s user management capabilities combined with it’s Drupal Taxonomy to content manage all content Drupal makes for a fantastic easy to setup social network.

Discussions

http://en.wikipedia.org/wiki/Comparison_of_social_networking_software
http://www.best-php-scripts.com/social_networking.htm
http://www.makeuseof.com/tag/the-5-best-open-source-social-networking-software
http://www.vivalogo.com/vl-resources/open-source-social-networking-software.htm