Slack was built as an internal tool for a video game that failed.
In 2013, Stewart Butterfield and his team at Tiny Speck released Slack, a workplace messaging platform that had been built as an internal communication tool during the development of a multiplayer online game called Glitch.1 The game failed, but the chat system the team had built to coordinate their own work proved more valuable than the product they were trying to ship. Butterfield had experienced a similar pivot before. His previous company, Ludicorp, had been developing a game called Game Neverending when it produced Flickr, the photo-sharing platform, as a byproduct.
Slack launched publicly in February 2014 and reached one million daily active users within a year.2 The platform organized conversation into channels, replacing the undifferentiated inbox of email with themed, searchable streams. By 2019, Slack had more than twelve million daily active users across more than 600,000 organizations.3 Salesforce acquired the company in 2021 for $27.7 billion.
Slack was not the first workplace messaging tool. IBM Lotus Notes offered real-time messaging in the 1990s, and Microsoft launched Lync (later Skype for Business) in 2010. Microsoft Teams, released in 2017 as a direct competitor to Slack and bundled with Office 365, reached 270 million monthly active users by 2022.4
The shift from email to channel-based messaging altered workplace communication patterns in ways that researchers are still measuring. Cal Newport argued in A World Without Email (2021) that the constant stream of messages created a "hyperactive hive mind" workflow, where workers spent their days monitoring channels rather than doing concentrated work.5 A 2022 Microsoft study found that the average Teams user sent 42 percent more chats per week than in 2020.6