How do you find the thread with the conversation you need to carry on? That's the problem with Slack. Slack threads is where information goes to hide and die. "Ah, you did answer that two days ago? Where?"

There are two levels of organization - channels and threads, so it's not too bad to browse if reasonably setup. It also gives you an inbox with all of your unread threads, so that you can catch up quickly; and, you can mark a thread unread if you want to punt on it after reading.