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Understanding Slack Channels vs. Threads vs. DMs
Applies to: Slack Desktop App, Slack Mobile App
Article Type: Informational
Last Updated: 2026-07-10
Summary
The fastest way to annoy your coworkers on Slack is to use the wrong communication method. Posting a highly specific question in a massive company-wide channel creates unnecessary notifications for hundreds of people. This guide breaks down the "Slack Etiquette" of Channels, Threads, and Direct Messages (DMs).
Prerequisites
- No prerequisites — this is an informational reference guide.
Instructions
1. The Direct Message (DM)
A Direct Message is a private, 1-on-1 (or small group) conversation.
When to use it:
- You need to discuss a sensitive or private topic (e.g., HR issues, performance).
- You have a question that only one specific person can answer.
- You are asking a quick favor that no one else needs to see.
When NOT to use it:
- You have a general question about a project. (If you DM someone, and they go on vacation, no one else can see your question or jump in to help. Ask in the project channel instead).
2. The Channel
A Channel (indicated by a # hashtag) is a shared workspace for a group of people. Some channels are company-wide, while others are for specific teams or projects.
When to use it:
- You have an announcement for the whole team.
- You have a question that anyone on the team could potentially answer.
- You are sharing a file or a link that the whole team needs access to.
When NOT to use it:
- You are having a back-and-forth, 20-message conversation with one other person in the channel. (Move this to a DM or a Thread so you don't spam the rest of the channel).
3. The Thread (The Most Important Feature)
A Thread is a mini-conversation attached to a specific message inside a Channel. When you reply in a Thread, your message is neatly tucked away, and only the people participating in the thread get notified.
When to use it:
- Always. If someone asks a question in a Channel, you must use the "Reply in thread" button (the speech bubble icon) to answer them.
- If you post a file in a channel, use a thread on your own message to add extra context or ask for feedback.
When NOT to use it:
- You are starting a brand new topic that is completely unrelated to the original message. (Start a new message in the channel instead).
The "Should I tag @here or @channel?" Rule
If you are posting in a channel, you can type @here or @channel to force a notification on everyone's computer. Use this power very carefully.
- @here: Notifies everyone in the channel who is currently online and active at their computer. Use this for urgent questions that need an answer right now.
- @channel: Notifies everyone in the channel, even if they are asleep, on vacation, or on their phone. Use this only for massive emergencies (like a server going down) or critical company announcements.
Troubleshooting
| Symptom / Error | Potential Cause | Solution |
|---|---|---|
| I can't find a Thread I replied to | Lost in the channel | Click "Threads" at the very top of your left sidebar to see all your active threaded conversations |
| I accidentally sent a DM instead of posting in the Channel | Wrong window | You can copy the text, delete the DM (click the three dots > Delete), and paste it into the Channel |