Acquainted - A simple tool to create conversational polls and surveys
Slack - A messaging app for teams who see through the Earth!
Expose - A beautiful, open-source, tunneling service - written in PHP
9mCollab - Collaborate (efficiently) Conclude (fast) Contribute (in the knowledge base)
Init.ai - Init.ai is the simplest way to build, train, and deploy intelligent conversational apps
Mattermost - Mattermost is an open source alternative to Slack.