Slack organises workplace conversation into channels — persistent, searchable rooms per team, project, or topic — and in doing so pulled a generation of offices out of email threads. The Android app is a full client: messaging, huddles for quick audio and video, file sharing, and an enormous catalogue of integrations with the tools teams already use. Salesforce has owned Slack since 2021.
The most important thing to know before adopting it is what the free plan no longer keeps. Since a 2022 policy change, free workspaces can only see messages and files from the past 90 days; older history still exists on Slack's servers but stays hidden until someone pays. Equally worth knowing: on paid plans, workspace admins can gain access to message content, including some private conversations, depending on plan and settings. Slack is a workplace tool, and it behaves like one.
The hub for a distributed team
Remote and hybrid companies run on channel structure: announcements in one place, each project in its own room, decisions searchable later. The mobile app makes catching up between meetings practical, and notification controls decide whether that is a feature or a leash.
Quick calls without scheduling
Huddles turn any channel or direct message into an instant audio or video call with screen sharing. For the thirty-second question that would otherwise become a calendar invite, this has become one of Slack's most-used additions.
Communities and volunteer groups — with a caveat
Plenty of open-source projects, alumni networks, and hobby groups run free Slack workspaces. It works, but the 90-day history window erases institutional memory, which is why many such communities have migrated to Discord or forums instead.
Channels, threads, and search
Public channels keep knowledge discoverable, private ones limit the audience, and threads stop side conversations from burying the main discussion. Search spans messages and files, though on free plans it only reaches back 90 days.
Huddles and clips
Lightweight audio and video huddles start with one tap and support screen sharing; clips let you record a short video or voice message for people in other time zones to play back later. Both reduce meeting load in practice.
App integrations and workflows
Thousands of integrations pipe alerts from code repositories, ticketing systems, calendars, and monitoring tools into channels, and Workflow Builder automates routine forms and reminders without code. This ecosystem is much of why teams find Slack hard to leave.
Slack Connect for external partners
Paid workspaces can share channels with clients, vendors, or agencies, replacing sprawling email chains with a shared room while each side keeps its own workspace. Admin controls decide who may start such channels and with whom.
