HeySpace - HeySpace is the only free task and simple project management software with communication and collaboration feature.
Rivers IM - Simple, fast & secure team collaboration platform
Slack - A messaging app for teams who see through the Earth!
Skarpline - Skarpline provides centralized enterprise messaging, link sharing and file management to improve productivity.
Infolio - All-in-one project collaboration suite for fast results and easy teamwork
Anologue - Disposable online chat.