If it will matter after today, don't talk about it in a chat room
The problem with "trying it with my team for one sprint" is that I now need to have a long conversation with legal. How will the service provider handle the content (discussions, screenshots, code snippets) that my team will upload? Do our current customer contracts contain any clauses that complicate the use of external discussion sites? In the unlikely event that the service offers the option to host it locally -- who is going to deploy it, configure it, set up security and authn/authz around it?The real answer is: just fucking use email. Why is email not  one of the options suggested in the TFA? It's universally available, durable, allows long-form conversation and thoughtful deliberation, doesn't tell you that "someone is typing," and offers you the luxury of checking it at a set interval only a few times per day.The way many organizations have collectively abandoned email in favor of instant messaging is a travesty.