Slack launched in 2013, created by Stewart Butterfield and his team at Tiny Speck — it actually originated as an internal communication tool built while they were developing a game called Glitch. Based in San Francisco, Slack quickly became the fastest-growing business app of its time, going from zero to a million daily active users in less than a year.
The platform transformed how teams communicate at work. Instead of email threads, Slack introduced channels organized by topic, direct messages, file sharing, and (crucially) integrations with thousands of other tools. The ability to connect services like GitHub, Jira, Google Drive, and Salesforce directly into chat conversations changed workplace workflows across industries.
Slack went public via direct listing on the NYSE in June 2019. In December 2020, Salesforce announced its acquisition of Slack for $27.7 billion — one of the largest software acquisitions in history at that time. The deal closed in July 2021.
Under Salesforce, Slack has been integrated into the broader Salesforce ecosystem while maintaining its identity as a standalone product. The platform serves over 750,000 organizations and millions of daily active users. Slack has added features like Huddles (audio/video calls), Canvas (collaborative documents), and AI-powered search and summarization. The app’s cultural impact is hard to overstate — “Slack me” has become a workplace verb, and its channel-based model has influenced virtually every team communication tool that followed.
