Slack isn’t just another office collaboration app. The company has been called, “the fastest-growing workplace software ever.” Recent press reports claim that “users send more than 25 million messages each week,” and that the company is, “adding $1 million to its annual billing projections every six weeks.”

Smelling an opportunity, investors just plowed $120 million into the company, giving it a $1.12 billion valuation.

“Our subscription revenue is growing about 8 percent monthly, before we add new sales,” says Slack’s business analytics lead Josh Pritchard. “This is, as far as I know, unheard for an enterprise SaaS company less than seven months after launch.”
Perhaps even more surprising, Slack’s user retention stands at an astonishing 93 percent.

How does Slack get its users hooked?

On the surface, no single factor seems to set Slack apart from a plethora of other online collaboration tools.
However, a closer look using the model described in the book Hooked: How to Build Habit-Forming Product, reveals the user psychology behind the company’s success.
A habit is an impulse to take an action automatically, with little or no conscious thought.
Slack’s ability to quickly form a habit could be the key to the company’s tremendous customer loyalty and high engagement.
Slack leads users repeatedly through a cycle called a “hook.”
The four steps of the hook include a trigger, action, reward, and investment, and through successive passes through these hooks, the new habit is formed.

The Slack Habit
The Slack team understood that it is much easier to displace an existing habit than to create an entirely new one. Slack doesn’t try to radically change user behavior. Instead, it makes existing behaviors easier and more efficient.

Slack also meets one of the most important prerequisites required to form a new habit: the key behavior occurs frequently. The company says the average Slack user sends 40 messages a day.
Habituated users send twice as many.

Slack’s Triggers Are a Cue to Take Action
Users keep Slack open all day on a variety of devices and receiving a notification prompts opening Slack.

Pritchard says, “It becomes a way of saying to your co-workers ‘I am at work and I am available.’”
The company has focused on making Slack easy to use when on the go. Slack user James Gill said, “I personally have found myself catching-up on things much more from my phone now than I ever did before.”
Though Slack clearly utilizes effective triggers in its own product to get users checking the app, don’t all those notifications overwhelm people? How can a company with the slogan, “Be less busy,” avoid perpetuating mindless multi-tasking with each new ping?

The key appears to be how Slack helps workers avoid other distractions.
Teams often use multiple tools in their work …