Open Source Social Network ( OSSN )!

Diaspora is a federated social networking service, designed to be a more privacy-aware alternative to Facebook . Share what you want, with whom you want.

Friendica is a distributed social network application which runs on commodity hosting platforms - PHP/MySQL/Apache. (If you can install Drupal or Wordpress you can probably install Friendica)

HumHub is a free social network software and framework built to give you the tools to make teamwork easy and successful.

GNU social is a continuation of the StatusNet project. It is social communication software for both public and private communications. It is widely supported and has a large userbase. It is already used by the Free Software Foundation, and Richard Stallman himself.

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.

Libertree is free, libre, open-source software which is intended to provide a way for people to create their own social network. Libertree social networks can be free from commercial influence and manifestation, such as behaviour tracking, user profiling, advertising, data mining and analysis, and covert information filtering.

SPIP is a publishing system for the Internet in which great importance is attached to collaborative working, to multilingual environments, and to simplicity of use for web authors. It is free software, distributed under the GNU/GPL licence. This means that it can be used for any Internet site, whether personal or institutional, non-profit or commercial.

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!

Social Network For Joomla to grow your communities with the least time.

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

Noosfero is a web platform for social networks with blog, e-Porfolios, RSS, thematic discussion and events agenda in the same system.Get to know, use it, participate and contribute to this free software project.

Welcome to the Futurenet Multimedia Club, the new social network which pay you to be social. We are already more than 1 millions users. Sign up to join our community.

Used to be called Sgrouples, now its MeWe offered by the company Sgrouples Inc. On its homepage their motto is "The World's Private Communication Network" and "Join the privacy revolution". Their big thing is privacy and that any and all content that you post is yours and yours only. It's run a lot like a private group in facebook.