Review of the Slack Communication Service

Slack lets you do without email

Hands using different digital devices for lots of functions

Ade Akinrujomu / Getty Images

Slack is a service available to business organizations looking to set a standard for online team communication. It's an acronym for "Searchable Log of All Conversation and Knowledge."

For a contemporary communication platform to be effective, it has to adapt to any device. Slack apps go where you like to work: in a web browser, synced to your desktop, and portable on a smartphone or tablet.

Frustrated with email and spam? Email is practically non-existent in Slack, and for a very good reason. You can use email, but it is the absence of email that directs your attention to the communication function. If you need email, Slack can send you notifications and alerts when someone on your team mentions you or includes you in a message, or when you follow a conversation, phrase, or keyword.

However, if you consider taking away the business of email, you may never look back. No more spam, no lost communication threads or wondering where you stored a message to your teammate or boss. Slack provides a communal workspace for your whole team.

How Slack Works

These are some of the multiple parts of Slack:


Channels are like chat rooms or public communication streams; the lifeblood of Slack for all of your organization. You can establish multiple channels, join a channel, and set up a channel with just a couple of clicks.

The hashtag, popularized by Twitter users, is a way to pull in conversations and people around a current event or topic of interest. Incorporating hashtags in Slack channels provide a means to create conversations, from general to specific.

For example, #general is a catch-all for day-to-day stuff, but you can decide that. Conversely, a #daily meeting would be specific.

In the early days of online communication and instant messaging, the original Internet Relay Chat (IRC) used hashtags, which not only came into widespread use but has since become a dictionary term.

Direct Messages

Direct messages are used for private conversations at any time with a team member. Direct messages are searchable content for you and the person you're messaging, including the files shared in the message.

So, you may send your boss a direct message with a report document attached. This message along with the document will be searchable.

Private Groups

The private groups are a one-to-many relationship, with your peers, like a development team, or a specific organizational unit, like HR or an executive team.

In Slack's private groups, conversations are in real time, much like the way instant chat works. Since history and search are provided in the private groups, there's a rich stream of communication that you can access from no matter where you're logged in.


All of Slack's content is searchable from one search box. Conversations, files, links, and even content that's integrated from Google Drive or tweets.

You can narrow your search to channels using a filter, or perhaps you prefer more options to search a colleague associated with an open channel.


A cool agent called Slackbot is like your own personal assistant that can give you more information about things, reminds you to do things like calling your wife at lunch, and more.

Slackbot can send automated chat responses when a word or phrase is mentioned, which is helpful in keeping you in conversations when you're away or playing hooky.

Integrate Slack With Other Services

Connection with other services like Google Drive, Google Hangouts, Twitter, Asana, Trello, Github, and many others can be pulled into conversations and made visible in the channel, private group, or direct message.

You can let the Slack team know if there is an integration service you would like to add and they can help expedite.

Slack Pricing

Slack has three pricing options; a free, standard, and plus plan.

The free plan is free forever and includes up to 10 integrations and 5 GB of storage. You also get two-factor authentication, two-person voice and video calls, apps for mobile and desktop devices, and a search function for up to 10 thousand of your team's messages.

The standard Slack plan features advancements from the free plan, including 10 GB of file storage for each team member, priority support, guest access, unlimited apps, and service integration, unlimited searching, group voice/video calls, custom profiles, retention policies, and more. 

The most expensive plan offered by Slack is called their plus plan. You get not only everything that the standard and free plan has but also 24/7 support with a 4 hour response time, 20 GB of storage per member, real-time Active Directory syncs, 99.99% guaranteed uptime, Compliance Exports of all messages, and SAML-based single sign-on (SSO).

How Slack Started

Slack was founded by Stewart Butterfield and first used internally by the Tiny Speck company, a San Francisco-based technology team. Slack's core team built Flickr, the no-nonsense photo sharing and storage application.

In the midst of developing a gaming application called Glitch, according to James Sherrett, head of marketing, this 45-member team came up with a communication tool that as Sherrett says, had "sent only 50 emails during a three-year period." The aha! moment came when they realized communication can "change the dynamic the way that you work with your team," says ​Sherrett.

Slack launched in 2013 and quickly grew to have 8,000 customers within the first 24 hours. Over the years, with more funding and customers, it had over one million daily active users by 2015.