Slack

Slack has transformed how teams communicate at work. Launched in 2013 and acquired by Salesforce for $27.7 billion in 2021, Slack is used by over 20 million daily active users and has become synonymous with real-time workplace communication. For millions of knowledge workers, Slack has replaced email as the primary way to collaborate with colleagues.

The genius of Slack is channels — topic-specific chat rooms that organize conversations by project, team, topic, or anything else. Instead of long email threads buried in individual inboxes, conversations happen in shared channels where everyone involved can see, search, and contribute. #marketing, #engineering, #q4-planning, #random — each channel is a persistent, searchable record of every discussion.

Direct messages work exactly as expected — one-on-one or small-group conversations separate from channels. Huddles, introduced in 2021, enable quick audio (or video) conversations from within Slack without the overhead of scheduling a meeting. For spontaneous questions and quick syncs, Huddles are faster than Zoom and more personal than text.

Slack's search is exceptional. Every message, file, and link ever shared in a workspace is fully searchable. Finding that conversation about a vendor from eight months ago, or locating the design file your designer shared last quarter, takes seconds. For teams that run their business in Slack, this institutional memory is invaluable.

Workflows (available on paid plans) let teams automate routine processes without code. Set up a workflow that sends a daily standup form to a channel every morning and compiles responses automatically. Or create a request intake form that routes to the right person. Slack Canvas, a document layer within Slack, allows teams to create reference materials that live alongside their conversations.

The integration ecosystem is enormous — over 2,600 app integrations connect Slack to GitHub, Jira, Salesforce, Google Drive, Zoom, and virtually every business tool. Notifications from external tools flow into Slack channels, keeping your team informed without forcing them to switch contexts.

The free plan's 90-day message history limit is a common pain point — teams lose access to older messages, which can be disruptive for knowledge management. Paid plans unlock unlimited history plus more storage and premium features.