The case for public Slack channels only (no DMs).

Source

Working at a company with a distributed team and hybrid work, a lot of work gets done on Slack. Slack can be very noisy, and I used to wish that fewer people would post in public channels, instead using direct messages (DMs). However, I am starting to think that over the long run, defaulting to public channels instead of DMs is best. Here, I try to explain why.

Warning: low novelty of ideas. Most likely LLMs can regurgitate everything in this post. This post is my attempt to explain these arguments coherently to myself and highlight which ones I find most persuasive.

Reason 1: context transfer is annoying

Because DMs are private unless explicitly shared, bringing a third party into a conversation is really difficult. For example, if you are debugging code with colleague A and have typed out 100 messages, but realize the bug might have something to do with code owned by colleague B, you would need to forward all 100 messages to B in order for them to have the proper context. This doesn't happen super often in my experience, but becomes more common in large teams. Avoiding this context transfer alone is an important reason to default to a public channel.

Posts in public channels are searchable by all users in a Slack workspace. If you post about things like fixing common bugs, having this information publicly available helps people solve their own problems in the future. The value of a historical cache of messages grows with time. Every inquiry sent as a DM is an inquiry not available for the public record.

Reason 3: input from unexpected people

Sometimes you choose who to DM based on who you know can help and who you expect to be available to help. Generally this tends to be junior people. However, more senior people sometimes are available. Sending things in public channels allows them to weigh in if they choose.

(anti-) Reason 4: notifications are flexible

Often people's biggest concern with sending messages in public channels is sending everybody in the channel a notification. This does seem to be Slack's default setting. However, notifications can be adjusted, and people can turn off notifications that aren't relevant. Tagging people with an @ mention is an effective way to notify just that specific person.

When would I still recommend a DM?

There are still reasons to send a DM: essentially cases where none of the reasons above apply. For example:

  • Private information of any kind
  • Things with no search relevance in the future (eg "is lunch today good?")
  • Things where no input from third parties will occur (eg scheduling a 1:1 meeting)

Conclusion

Although I don't 100% believe in the "no DM" philosophy for Slack, I think I understand the core arguments for it. I think the downsides of notifying many people depend on the size of channels and the total number of people at a company...

Also, in case it wasn't clear, the advice in this article is not super specific to Slack, it likely also applies to MS Teams, Discord, etc.