What Slack is
Slack is a platform for team messaging and workplace collaboration built around channels: conversations are organized by team, project, or topic, with members discussing, sharing files, and using integrated apps inside channels, replacing part of email traffic. The company describes itself as the work platform that brings “conversations, apps, and customers together in one place”. Slack was acquired by Salesforce in 2021 and operates as a Salesforce company. Core features include channels and direct messages, Huddles audio and video meetings, Clips for recorded updates, Slack Connect for external collaboration, Canvas documents, Lists for projects, the Slack Marketplace with over 2,600 apps, and the no-code Workflow Builder.
Usage and boundaries
Slack’s typical uses are day-to-day team communication and cross-team collaboration: syncing progress in project channels, spinning up a Huddle for a quick call, automating routine notices with Workflow Builder, and working with external partners over Slack Connect. It is not a document system or project manager in itself — Canvas and Lists cover lightweight document and task needs, while heavier knowledge bases and project tools usually stay separate and plug into Slack through integrations.
The company has been folding AI features into the product: channel and thread summaries, daily recaps, AI-powered search, and Slackbot positioned as “your personal AI agent for work”. Feature availability varies by plan and region, so the official pages are the reference. There is also a permission boundary to keep in mind: channel messages are visible to channel members by default, so sensitive material such as financial or HR details belongs in restricted private channels or dedicated systems rather than relying on a tool designed for open sharing.
Discussion in the show
In Weekly #005’s chapter “Dots：记忆、云电脑与上手体验” (Dots: memory, cloud computers, and first impressions), Guizang relays a case he saw on social media: someone gave Grok Bot some information, and Grok Bot posted his bank balance into Slack — “all his colleagues knew his financial data”, per the Chinese transcript. The example appears in a discussion of personal-agent permission boundaries: once an agent can post messages, it may publish things that were never meant for a shared channel. It is a third-party anecdote relayed by a participant to illustrate agent permission design, not a judgment on Slack itself. See the episode 005 chapter (Chinese transcript; no English transcript is available).
Frequently asked questions
What is Slack?
A channel-centered messaging and collaboration platform for organizations: teams discuss, meet, share files, and connect other work apps in channels. It has belonged to Salesforce since 2021. Note the word slack has other meanings — slack tide in boating, for instance — that dominate some searches.
Is Slack free?
There is a permanently free plan. Per the official pricing page, its limits stood at 90 days of message history and up to 10 app integrations as of October 2026; paid plans such as Pro and Business+ lift those limits and add administration features. Current plans and limits live on the official pricing page.
Where do I download Slack?
The official site is slack.com, offering Windows, macOS, and Linux clients, a browser version, and iOS and Android apps; downloads are listed on the official downloads page.
Slack vs Discord — which one?
They have different shapes: Slack targets work, organized around channels, app integrations, and enterprise collaboration; Discord leads with communities and voice; consumer messengers cover personal and lightweight work chat. The right choice depends on team size, compliance needs, and the existing toolchain, not on a feature checklist alone.