[domsom]

Picking the Slack / Chat argument: I don't think it should be expected to reply immediately. It's more like a lightweight inbox (when being tagged / DMed) that's easy to reply to (no greeting/regards required). Channels are a great place for async discussions that can be linked to and are kind of public so noone needs to decide beforehand whom to engage, and everyone can decide to join or leave the discussion without being cc'd forever.