open source messaging platform

See the following -

Open Source Software Has to Sell User Experience

Mattermost does open source the right way. Open source software that is to succeed in this new world is going to have to be better than anything else. You can't sell just openness anymore; it is added value, not a unique selling point. Open source software now has to sell user experience. In a way it is a simpler metric, and probably one that is going to change open source forever—for the better. An exemplar of this new way is Mattermost, the open source messaging platform. Sure, they weren't first to the game, because Slack blazed the trail...