Slack app privacy

Of course they are

Yes or no. It depends on the plan

Does anyone in management or HR know directly of an instance where private DMs that were legal and no other misconduct existed were actually read and used against an employee? I’ve been in leadership / management roles at two companies with slack or a competing product, and I know of zero such cases. (And I get a lot of gossip / juicy details on other topics) I fee like this might be theoretically possible, but barring illegal activity or harassment accusations etc, your garden variety dm moaning is fine.

When you are sitting at your laptop, the CEO is looking right at you through your webcam and you don't know it.