This article contains content that is written like an advertisement. (July 2022)
|Original author(s)||Stewart Butterfield, Eric Costello, Cal Henderson, and Serguei Mourachov|
|Developer(s)||Slack Technologies (Salesforce)|
|Initial release||August 2013|
|Operating system||Microsoft Windows, macOS, Linux, iOS, Android, Windows Phone (depricated)|
|Available in||12 languages|
List of languages
Chinese (Traditional), Chinese (Simplified), English (UK), English (US), French (France), German (Germany), Italian (Italy), Japanese (Japan), Korean (South Korea), Portuguese (Brazil), Spanish (Latin America), Spanish (Spain)
Slack is a cloud-based freemium cross-platform instant messaging service created by Slack Technologies and currently owned by Salesforce. While initially developed for professional and organizational communications, it has also been adopted as a community platform. Users can communicate through text messaging, file and media sharing, voice and video calls in private chats or within communities called "workspaces." The application incorporates IRC-style elements such as persistent chat rooms (referred to as channels) organized by topic, private groups, and direct messaging. In addition to these online communication features, Slack can integrate with other software. Slack can be accessed through web browsers, and dedicated clients are available for Windows, Linux, MacOS, Android, and iOS. In the past, a client was also available for Windows Phone devices, but support for it was discontinued in June 2018.
Slack originated as an internal communication tool used within Stewart Butterfield's company, Tiny Speck, during their work on the development of Glitch, an online game. These communication tools were initially built around the Internet Relay Chat (IRC) protocol and included scripts designed to automate and organize file exchanges among their development team. However, in October 2012, Stewart Butterfield came to the realization that Glitch was not going to bring necessary profits. As a result, he decided to change the direction of his company and repurpose the communication tools they had developed into a new product.
In 2012, Stewart Butterfield decided to name their upcoming product "Slack," which he said was derived from the phrase "Searchable Log of All Conversation and Knowledge," replacing the previous codename "linefeed."
In August 2013, Slack was launched to the public and continued to maintain compatibility with IRC, reflecting its origin. Additionally, it was also compatible with XMPP messaging protocols. However, in May 2018, the company chose to close down these corresponding gateways due to limitations inherent in those protocols.
In July 2020, Slack acquired Rimeto, a startup specializing in employee directories and profiles, with plans to rename the service and operate it as a standalone app. Almost a year later, in June 2021, its functionality launched as an optional feature within Slack named "Slack Atlas."
On December 1, 2020, Slack and Salesforce announced an agreement for Salesforce to acquire the company for approximately $27.7 billion, marking one of the most significant tech acquisitions at that time. The acquisition was successfully completed on July 21, 2021.
In March 2015, Slack announced it had been hacked for 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, Slack added two-factor authentication to its service.
On January 4, 2021, Slack suffered a significant outage that lasted several hours. From 10 AM ET until 3 PM ET, users could not log in, send or receive messages, place or answer calls, or use Slack 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 known as channels, which are organized by topic, as well as private groups and direct messaging functionalities. All content, including files, conversations, and people, is searchable within Slack. Users can express their reactions in the form of emojis to any message. Message history on Slack is limited to 10,000 most recent messages on the free plan.
Slack allows for communities, groups, or teams to join a "workspace" via a specific URL or invitation sent by a team admin or owner. A workspace can contain both public and private channels, with public channels being accessible to all members of the workspace. Both public and private channels can be converted interchangeably.
Direct messages enable users to engage in private one-on-one or group conversations, up to 9 participants. Group direct message can be converted into a private channel.
Slack integrates with many third-party services and supports community-built integrations, including Google Drive, Trello, Dropbox, Box, Heroku, IBM Bluemix, Crashlytics, GitHub, Runscope, Zendesk, and Zapier. In July 2015, Slack launched an integration with Google Calendar. Later, in December of the same year, a searchable directory was introduced consisting of over 150 integrations that users can install. In addition to these integrations, Slack offers users the ability to incorporate and customize chatbots known as "Slackbots." These chatbots can be configured to send notifications, reminders, or provide tailored responses to specific phrases, among other functions. Furthermore, Slack provides an application programming interface (API) that enables users to develop applications and automate various processes, including sending notifications based on input, generating alerts for specific conditions, creating internal support tickets, and more.
In March 2018, Slack partnered with Workday, a financial and human capital management firm. This integration allows employees to access co-worker information, organizational charts, benefits, feedback, and time-off requests within Slack.
In March 2022, Slack introduced a new voice conference feature known as "Huddles." Within a Huddle, users have the capability to mute or unmute themselves, share their screens, draw on a shared screen, and invite others to the call. In June 2022, Huddles received the additional functionality of video calls. Huddles are restricted to only two participants on free tiers, while paid plans offer the capacity for up to 50 participants.
Slack provides mobile apps for iOS and Android in addition to their Web browser client and desktop clients for MacOS, Windows, and Linux (beta). Slack is also available for the Apple Watch, allowing users to send direct messages, see mentions, and make simple replies. Slack has been made to run on a Super Nintendo Entertainment System via Satellaview.
Slack is a freemium product whose main paid features are the ability to search more than 10,000 archived messages and add unlimited apps and integrations. They also claim support for an unlimited number of users. When FreeCodeCamp attempted to switch its community of over 8,000 users to Slack in 2015, however, they experienced many technical issues and were advised by Slack support to limit their channels to "no more than 1,000 users (ideally more like 500)." That specific limit no longer applied by January 2017.
In August 2013, 8,000 customers signed up for the service within 24 hours of its launch. In February 2015, the company reported that approximately 10,000 new daily active users had signed up each week, and had more than 135,000 paying customers spread across 60,000 teams. By April 2015, those numbers had grown to 200,000 paid subscribers and a total of 750,000 daily active users. Late in 2015, Slack passed more than a million daily active users. As of May 2018[update], Slack had over 8 million daily users, 3 million of whom had paid accounts. At the time of its S-1 filing for IPO, dated April 26, 2019, Slack reported more than 10 million daily active users from more than 600,000 organizations, located in more than 150 countries.
In 2019, it was estimated that employees at large firms were sending over 200 Slack messages per week on average. From 2013 to 2019 the amount of time spent on work email had declined, which was attributed to the proliferation of Slack and its competitors Workplace (launched by Facebook in 2016), Microsoft Teams (launched 2017) and Google Hangouts Chat and Meet (launched in 2018).
In March 2015, the Financial Times wrote that Slack was the first business technology to have crossed from business into personal use since Microsoft Office and the BlackBerry. In 2017, New York magazine criticized the platform for being "another utility we both rely on and resent."
The digital rights group Electronic Frontier Foundation (EFF) has cautioned that "Slack stores and is able to read all of your communications, as well as identifying information for everyone in your workspace." They commended the company for "follow[ing] several best practices in standing up for users" concerning government data requests, such as requiring a warrant for content stored on its server, and awarding it four out of five stars in its 2017 "Who has your back" report; the EFF also criticized Slack for "a broad set of exceptions" to its promise to notify users of such requests, and for other privacy shortcomings.
Slack has been criticized by users for storing user data exclusively on cloud servers under Slack 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 also been criticized when used in free and open source projects for the inability to search for messages and discussions. With a traditional mailing list, one can use any search engine to find discussions of problems and issues. However, Slack channels are not indexed by search engines, so they cannot be searched using traditional tools.
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