[datazzz]

I worked at a company that insisted on no direct messaging and no private team channels. It was stressful and counterproductive, in fact in the short time I was there (I left) I counted 3 different chat services people were using to discuss work topics that were outside the company. No one wants to perform their job on a stage all day everyday. Unless you're actually a performer, I suppose. It was also nearly impossible to keep up with everything and nothing indicated what I really needed to focus on.

Also worked at a company that encouraged people into public channels for inter-team communication and into team channels for anything useful to your team, but didn't have obnoxious rules around it. Also allowed private team channels. Worked perfectly, everyone felt comfortable talking to just their team in the private channels, and everyone searched Slack for old technical answers all the time because they were actually there, which is about as close to proof it worked as you can get.

Also there should be a buddy for all new hires and you should get a month or 3 of DMs with them because asking every dumb new-person question in public is tough for introverts.