I have been a few months in on slack and love it! It made communication easy, instant and retrieval. Emails went down and a little dot followed everywhere on laptop, phone and Internet. However I also found myself replying to every trivial message even when I was slammed with work. I noticed how small issues became big just because an exec replied to it and how slack (read co workers) started controlling my day than myself. I concur that it is not the tool but how we use it. I believe just like any other process an organization needs to define policies around what goes on slack and what needs an immediate response. I am sure over time as more companies face this situation the best practices and management consultants would surface up. Till then such articles help.