BuddyCloud provides tools, libraries and services for secure cloud & on-premise user and group messaging.

Diaspora is a nonprofit, user-owned, distributed social network that is based upon the free Diaspora software.

FreezeCrowd is a social networking site for college students and alumni.

GNU social is a continuation of the StatusNet project. It is social communication software for both public and private communications.

Hubzilla is a powerful platform for creating interconnected websites featuring a decentralized identity, communications, and permissions framework.

Libertree is a free, libre, open-source software that lets people create their own social network.

BuddyPress inherits and extends upon the integral functional elements of the WordPress engine including themes, plugins, and widgets.

Ello is a community to discover, discuss, publish, share and promote the things you are passionate about.

Friendica (Friendika or Mistpark) is open source software for a distributed social network. The focus is on effective privacy settings and easy installation …

Hangouts is an instant messaging software developed by Google.

Known is a publishing platform that allows its users to share their stories online.

Minds is an open source social networking service.