Slack Technologies Inc.

Slack Technologies, Inc. is an American international software company founded in 2009 in Vancouver, British Columbia, Canada. Its core team is largely drawn from the founders of Ludicorp, the company that created Flickr.

Slack began as an internal tool for Stewart Butterfield’s company Tiny Speck during the development of Glitch, an online game. “Searchable Log of All Conversation and Knowledge” is a backronym for “Slack”.

Outside its headquarters in San Francisco, California, the company operates offices in Dublin, Vancouver, New York City, Toronto, Denver, London, Tokyo, Pune, Paris, and Melbourne.

In March 2015, Slack announced it had been hacked over four days in February 2015, and that some data associated with user accounts had been compromised, including email addresses, usernames, hashed passwords, phone numbers, and Skype IDs. In response to the attacks, company added two-factor authentication to its service.

In June 2019, Slack Technologies went public on the New York Stock Exchange via a direct stock listing. On December 1, 2020, Salesforce announced its acquisition of Slack for $27.7 billion.

On January 4, 2021, Slack suffered a large outage which lasted several hours. From 10 AM ET until 3 PM ET users could not log-in, send or receive messages, place or answer calls, and use connections. After 3 PM, most of the core features became operational, except for push notifications, email, and third-party integrations including Google Calendar and Outlook Calendar.

Slack offers many IRC-style features, including persistent chat rooms (channels) organized by topic, private groups, and direct messaging. Content, including files, conversations, and people, is all searchable within Slack. Users can add emoji buttons to their messages, on which other users can then click to express their reactions to messages.

The company’s free plan allows only the 10,000 most recent messages to be viewed and searched.

Slack has been criticized by users for storing user data exclusively on cloud servers under the company’s control. This is found to be a particular issue for users with large teams, who experienced issues with connectivity within the app, access to archived messages, and the number of users for a given “workspace”.

Slack has additionally been criticized for a retroactive 2018 change to their privacy policy, allowing access to all public and private chat messages by workspace administrators, without the need of consent from any parties using the app. According to the policy, users would not be notified when their information is being accessed.