* [Buddycloud](http://buddycloud.com/) - Tools, libraries, services and a community to build user-to-user, group and social messaging into your app. Saves time. Scales up. Supports you. ([Source Code](https://github.com/buddycloud)) `Apache``Java`
* [Buddycloud](http://buddycloud.com/) - Tools, libraries, services and a community to build user-to-user, group and social messaging into your app. Saves time. Scales up. Supports you. ([Source Code](https://github.com/buddycloud)) `Apache``Java`
* [BuddyPress](https://buddypress.org/about/) - A powerful plugin that takes your WordPress.org powered site beyond the blog with social-network features like user profiles, activity streams, user groups, and more. ([Source Code](https://buddypress.svn.wordpress.org/trunk/)) `GPLv2``PHP`
* [BuddyPress](https://buddypress.org/about/) - A powerful plugin that takes your WordPress.org powered site beyond the blog with social-network features like user profiles, activity streams, user groups, and more. ([Source Code](https://buddypress.svn.wordpress.org/trunk/)) `GPLv2``PHP`
* [Classified-ads](http://katiska.org/classified-ads/) - Messaging app originally designed to replace usenet news - requires no server-side support due to P2P nature. Includes private messages, profile data, search and voip. ([Source Code](https://github.com/operatornormal/classified-ads)) `LGPLv2``C++`
* [Discourse](http://www.discourse.org/) - Advanced forum / community solution based on Ruby and JS. ([Source Code](https://github.com/discourse/discourse)) `GPLv2``Ruby`
* [Discourse](http://www.discourse.org/) - Advanced forum / community solution based on Ruby and JS. ([Source Code](https://github.com/discourse/discourse)) `GPLv2``Ruby`
* [Elgg](https://elgg.org/) - A powerful open source social networking engine. ([Source Code](https://github.com/Elgg/Elgg)) `GPLv2``PHP`
* [Elgg](https://elgg.org/) - A powerful open source social networking engine. ([Source Code](https://github.com/Elgg/Elgg)) `GPLv2``PHP`
* [Flarum](http://flarum.org) - Delightfully simple forums. Flarum is the next-generation forum software that makes online discussion fun again. ([Source Code](https://github.com/flarum/flarum)) `MIT``PHP`
* [Flarum](http://flarum.org) - Delightfully simple forums. Flarum is the next-generation forum software that makes online discussion fun again. ([Source Code](https://github.com/flarum/flarum)) `MIT``PHP`