Mastodon - Mastodon is a decentralized, open source social network. This is just one part of the network, run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome!
Slack - A messaging app for teams who see through the Earth!
Gab - Gab is an ad-free social network dedicated to free speech.
MS SharePoint - Share, organize, and discover information with Microsoft SharePoint. Learn about SharePoint Online, OneDrive for Business, and Apps for SharePoint
Diaspora - The online social world where you are in control.
Jostle - A new kind of employee intranet that drives engagement & workplace culture. Achieves social participation in work relevant way. Participation rates are over 85%.