Crabgrass is social networking, group collaboration, and network organizing Web application. It consists of a solid suite of group collaboration tools such as private wikis, task lists, a file repository, and decision making tools. Work is currently being done on a large user interface overhaul, better social networking tools, blogs, and event calendars, as well as better support for collaboration and decision making among independent groups.
Cysphere is an integrated social networking server for smaller virtual communities. It provides a private mailbox, public and private discussion forums, and simple file sharing, and makes it as simple as possible for users to communicate over the Web in a secure way. It includes an embedded Web server and SQL database and requires no installation or maintenance.
The Community Builder (CB) suite extends the Joomla! user management system, and allows you to use Joomla! to build a customizable social networking Web site. Its key features are extra fields in a profile, enhanced registration workflows, user lists, connection paths between users (friends), administrator-defined tabs and user profiles, image upload, front-end workflow management, and integration with other components, like PMS, Newsletter, Forum, and Galleries. Many plugins are available for adding more features. CB is compatible with all versions of Joomla! 1.5 native, Joomla! 1.0.x native, and Mambo 4.5.2-4.6.5. CB allows multi-criteria user searches, full field controls of core fields, AJAX email and username checkers, image and integer fields, custom validations, and many more features.