Four puzzle pieces, with three interlocked and one resting off to the side

Collaborate effectively in channels

Lesson overview

Sara recently joined Acme, a company that uses Slack. In this lesson, you’ll learn how Sara and her team collaborate effectively in channels by using mentions and reactions, sharing files, and formatting messages.

Sara’s experience before Slack

At her previous company, Sara found that communication happened in many different places. She received a constant stream of emails to her inbox, even if they weren’t very valuable or didn’t apply to her. Files were shared with individuals, and decisions were often made without everyone knowing what was going on. These communication silos made it difficult to align on work, track information, and stay up to date.

How Acme uses Slack

  • People at Acme use mentions to get the attention of specific people to move work forward.
  • Files and conversations exist side by side in channels, which means everyone always has access to the most current information.
  • Sara has noticed that people respond efficiently to each other using reactions.

Get the attention of specific people with a mention

Mention a teammate

Sara needs to get the attention of someone specific to help move work forward, so she mentions Lisa directly in the message she sends to the channel. Lisa gets notified that someone needs her help, and the whole team can see what’s happening in the conversation.

Share files with the team

Upload a file

When Sara works with her team, she wants files and conversations to exist side by side so everyone has access to the most up-to-date information, making it much easier to get work done. Sara is ready to share a file so she shares it in the channel alongside the conversation.

Respond efficiently with reactions


Sara and her teammates share documents to review in the channel. They could acknowledge each other by writing, “Thanks. Taking a look!”, but sending a new message would mark the channel as unread for all other members and the comment wouldn’t add much value to the conversation.

Instead, Acme uses a shared language for emojis to simplify communication. For example, when a teammate is reviewing a document that’s shared in the channel, they react with the eyes emoji to let everyone in the channel know they’ve seen the message and they’re working on the review.

Keep things tidy with message formatting

Format messages

Sara is sending a message that outlines some suggestions for the document Liza shared. By taking the time to neatly format her message, Sara ensures that everyone in the channel can quickly scan the content and understand the next steps.

Edit or delete your sent messages

Edit message

Sara needs to add something else to the list of suggestions she included in her previous message. She has the flexibility to edit her message even after it’s been sent.

Your next steps

💡 Mention colleagues in a channel to get their attention.

💡 Add a reaction to a message in a channel.

💡 Upload a file and share it in a channel.

💡 Try out some formatting techniques on your next message.

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