Jamroom!

Social networking in a box. Build a social network for your company, school, sports team or niche community all based on the power and flexibility of WordPress. Install BuddyPress directly through your WordPress dashboard plugins page, or download it manually from the WordPress.org plugins repository.

Open source PHP social networking software with Facebook-style newsfeed. Free plugins, themes, easy installation and auto-updates.

The award-winning Open Source Community software for Joomla. JomSocial is a powerful social networking software, loaded with plenty of social network features to empower your community such as entrepreneur circles, gamers clubs, hobbyist communities, artist fan pages and a lot more!

Elgg is a leading open source social networking engine which can be used to power your social network.

Ning is the social platform for the worlds interests and passions online. Millions of people every day are coming together across Ning to explore and express their interests, discover new passions, and meet new people around shared pursuits.

SocialEngine is a PHP-based white label social network platform. Advanced social networking features include blogs, photo albums, user groups and forums, providing complete control over the layout and functionality of your social network, community, or portal.

The ultimate solution for your social network. phpFox is easy to use, easy to customize and packed with advanced social networking features found on top community websites! Get a 14-days trial for FREE now. at https://www.phpfox.com/#foxsite_trial

Dolphin is an advanced social networking software with a rich history of development. It's implemented in PHP with the core being open-source, hosting and additional features are available through Boonex, the company behind it.