Slack: The smart person's guide

This comprehensive guide covers the common use cases of Slack, its technical benefits and limitations, and what to know before adopting the cloud-based collaboration tool.

Image: Slack

In the information economy, sorting through the internal discussions in an organization can be a laborious task, particularly when discussions are conducted through long chains of emails. The goal of Slack is to simplify internal communication in order to increase efficiency.

This guide to Slack is both an easily digestible introduction to the service, as well as a "living" guide that will be updated periodically to keep IT leaders in the loop on new features, integrations, competitors, and ways in which this technology can be leveraged.

SEE: All of TechRepublic's smart person's guides

Executive summary

  • What is Slack? Slack is a cloud-based tool that is intended to be the center of workplace collaboration, and to integrate with other products your organization uses.
  • Why does Slack matter? Slack attempts to increase productivity by simplifying communication.
  • Who does Slack affect? Practically any group can use Slack, and the free tier has no limit to the number of users that can be added to a group.
  • When is Slack happening? Slack launched in August 2013, though the developers have continuously improved the service, with key features being added in 2016.
  • How do I get Slack? You can create your own Slack team for free. Paid tiers are available with additional features, and education and nonprofit organizations are eligible for discounts.

What is Slack?

Slack is a cloud-based collaboration tool that aims to be the central platform through which teams communicate. In the most simplistic view, Slack is an email replacement, though it operates more like group messaging—foregoing the formalities of composing emails, and having various channels to which users can be assigned, rather than the comparatively complex task of managing mailing lists.

In contrast to other vendors and established competitors that have a tendency toward vertical integration of features, Slack can integrate with a wide variety of third-party services. Among these are developer tools such as Bitbucket, GitHub, and IFTTT; file storage services such as Google Drive, Box, and Dropbox; project management tools such as JIRA and Zendesk; and social media platforms such as Twitter and Foursquare.

Slack can run in practically any modern browser. Desktop applications are available for Windows and Mac OS, as well as beta support for Linux (currently Ubuntu and Fedora). Mobile apps are available on iOS and Android, with beta support for Windows Phone.

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Why does Slack matter?

The goal of Slack is to increase productivity by simplifying communication, while putting Slack in the middle of your communication workflow. To do so, Slack designers focus on solving problems that users do not know they have—a task so abstract, it is easier to describe in an example than define it.

Take, for example, the not altogether uncommon task of sending a link to an article via email. The typical greeting and closing and the automatically added signature are extraneous (though polite) components of the purpose of this email, while the task at hand—sending a link—is stuck somewhere in the middle of this text. The link itself needs some amount of context, particularly if the URL has no particular semantic value—for instance, you would never guess that this page explains enabling two-factor authentication for Apple ID by looking at the URL, or that this YouTube video is a commercial for the soft drink Mitsuya Cider. When you post a link in Slack, it automatically generates a description of the link, reducing the need to provide context for sending a link, and avoiding "risky clicks" for those who do not know what is being linked. This works in a context-dependent way, as well—linking to an article displays the headline, writer byline, and publication name.

Slack features a variety of these helpful utilities. In an interview with CNET, Slack cofounder Stewart Butterfield noted that "There's a set of features that people want that they don't even know that they want... but when they get them, they like them."

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Who does Slack affect?

Practically any organization—or, generally, loose association of people—can use Slack. The free tier has no limitations on the number of users that can be added to a group; it retains and indexes the last 10,000 messages for search, and it can utilize 10 service integrations. Because of this, Slack is gaining momentum as a communication platform outside of work contexts.

There are additional features available for paid plans. The Standard plan, which is $6.67 user/month, billed annually, stores unlimited messages, and can use an unlimited number of integrations. It also includes custom retention policies, user groups, Google Authentication / Apps for Domains sign-in, guest access, and a configurable email ingestion service. For most midsize organizations, the Standard plan should be adequate. The Plus plan, at $12.50 user/month billed annually, includes SAML-based single sign-on, and compliance exports of message history, and real-time active directory sync. A forthcoming Enterprise plan will allow for federation across multiple teams, and consolidated billing across teams.

Organizations that require an extensive level of collaboration between group members can benefit from adopting Slack. Programmers, journalists, and other professions that are particularly likely to be spread across different offices, have a high number of remote and/or freelance workers, or have group members that are often traveling stand to gain the most from adopting Slack. Conversely, extremely client-focused businesses such as a medical practice or a real estate agency are less likely to need Slack, as more communication is done with the customer than within the organization.

Slack's survey results provide an interesting look at how organizations have changed after adopting Slack. According to the company, the number of emails generated by groups that adopted Slack was reduced by an average of 48.6%, while meetings were reduced by an average of 25.1%. 80.4% of respondents indicated that the use of Slack has increased transparency.

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When is Slack happening?

Slack was originally developed as an internal communication tool for the team working on the computer game "Glitch" (which has been forked as "Eleven"). While the plans for that game did not meet expectations, Slack held more promise as a product, and was publicly launched in August 2013. Since then, the developers have been actively soliciting feedback and implementing new features based on user requests.

Voice calls are currently in beta, with users on the free tier limited to 1:1 calling, while paid tiers can have group calls of up to 15 people. If you prefer not to use Slack's internal implementation, it is (and will continue to be) possible to use Skype integration instead.

Message threading is also being tested internally at Slack. Because of the current flat nature of conversations, sorting out multiple discussions that can happen in a given room can be somewhat daunting of a task, which the Slack team is seeking to remedy without impeding the flow of conversations.

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How do I get Slack?

If Slack is right for you, you can create your team for free to start evaluating the platform. For qualifying educational institutions, Slack offers discounts of 85% from the annual price of the Standard and Plus plans. For nonprofit organizations, Slack offers free access to the Standard plan.

Alternatively, Atlassian's HipChat offers the same features of Slack, with the same mobile and desktop clients (minus Windows Phone), and largely the same set of integrations. In contrast to Slack, HipChat can be hosted in the cloud or internally, and HipChat Plus pricing is a flat $2 per user/month, which is substantially lower than any of Slack's paid tiers. At present, HipChat Plus has a more mature 1:1 voice and video calling system than Slack, though group calls are not supported. Both HipChat and Slack can use BlueJeans integrations for video conferencing.

For those who want an open-source alternative to Slack, the Matrix project is building an open communication platform, which you can try at

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About James Sanders

James Sanders is a Java programmer specializing in software as a service and thin client design, and virtualizing legacy programs for modern hardware.

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