More than six million people use Slack daily, spending on average more than two hours each day inside the chat app. For many employees, work life is contingent on Slack, and surely plenty of us use it for more than just, say, work talk. You probably have a #CATS and a women-only channel, and you’ve probably said something privately that you wouldn’t want shared with your boss. But that’s not really up to you.

When you want to have an intimate or contentious chat, you might send a direct message. Or perhaps you and a few others have started a private channel, ensuring that whatever you say is only seen by a handful of people. This may feel like a closed circuit between you and another person—or small group of people—but that space and the little lock symbol aren’t actually emblematic of complete privacy.

Do Slack employees have access to your chats? The short answer is: sort of. The long answer is… below. Can your company peek at your private DMs? It’s entirely possible. Slack’s FAQ pages help elucidate some of these concerns, but at times the answers are frustratingly vague and difficult to navigate. So we dug into it for you. Read more to find out what Slack—and your company—is actually doing with your data.

Source: What’s Slack Doing With Your Data?

The short is:
Yes, there are slack employees that can view your data. Channel owners can see everything in a channel, also direct messages. Slack gives your data to law enforcement upon request and won’t inform you. They don’t (and say won’t) sell it to third parties. Deletion is deletion. Slack, like any other company, can be hacked. Caveat emptor.