Having chat rooms for specific topics or projects have become quite popular. IMHO it is a nice addon for development and deployment lifecycle management. HipChat or Slack are some popular providers. If you want to have an internal chat system, letschat is a quick way to accomplish that. It has some flaws, debugging LDAP was a horror, but basically is good enough in its vanilla state. Take as it is and its free (MIT License). We use it currently for receiving notifications from our continuous integration system.