I can't recommend Slack more. It has an amazing web-app, works perfectly and the basic plan has no limit on users. I've tried both HipChat and Campfire, and I a

I can't recommend Slack more. It has an amazing web-app, works perfectly and the basic plan has no limit on users. I've tried both HipChat and Campfire, and I always felt that they were never the primary focus of the companies that own them.