This is how Slack became a powerhouse of the remote working world

The workplace-productivity company became essential amid the coronavirus crisis,
and in the process, rediscovered itself.

Slack had more new users in two weeks of the coronavirus than it had in the previous six months.

9 March, 2020, was always going to be a big day for Slack.

The Monday after the start of daylight saving time in the United States brings the US and Europe an hour closer together, and the extra hour of workday overlap between the two continents has traditionally resulted in a jump in simultaneous users on the digital messaging platform.

But that Monday, something unexpected happened.

Concerns about the coronavirus had been taking hold the previous week across the United States. Amazon, Apple, Facebook, and Google began to tell employees to work from home. Stanford University cancelled in-person classes. MGM postponed the launch of the 25th James Bond movie. Its title: No Time to Die.

“We expected to see a spike on that Monday morning,” says Cal Henderson, Slack’s CTO. The company has “an internal channel that automatically posts when we set a new record,” and its automated chime went off more than once that day: Slack’s worldwide connected users hit an all-time high. The number of daily messages sent did, too. “We didn’t build Slack for a global pandemic,” says Henderson, just over a week after hitting this benchmark. “But it is hugely applicable to what’s happening in the world.”

Even if you ignored the news as the pandemic unfolded and were just watching Slack’s user stats, you would have known something epic was happening. Slack hit the milestone of 10 million simultaneous users for the first time ever on 10 March. Six days later, on 16 March, Slack notched 11 million. Seven days after that, on 23 March, Slack reached 12 million simultaneous users. Slack had more new people using it at the same time in two weeks of concern about the social spreading of the novel coronavirus than it had added in the previous six months. And the pace accelerated: Slack added another 500,000 simultaneous users in just two days at the end of March.

In short order, as tens of millions of employees started working from their kitchen tables, kids’ playrooms, or propped up in their beds, Slack made it possible for many of them to have conversations, ask questions, share information, make decisions. The platform combines the superficial simplicity of smartphone text messaging with the ability to separate and chronicle streams of workplace communication in a way that reproduces the culture of the open-plan office. The strings of messages are democratic, energizing, and also sometimes distracting. In the pandemic, Slack let the people who could keep working, keep working.

As business swerved to avoid the coronavirus, it was turning to Slack for help.

Before the pandemic, Slack counted 65 of the 100 largest public companies in the U.S. as customers, along with The Washington Post and The New York Times, and a dozen agencies of the American government (including the State Department and, reportedly, the National Security Agency). Slack had defined this new form of workplace communication and had grown in less than seven years to more than 110,000 paying customers and $630 million in annual revenue. But investors had been wary of the company since it went public in June 2019, because of its slowing growth, lack of profitability, and competition from Microsoft, which has a competing product called Teams that is free. The company reported its fiscal 2020 earnings on March 12, the day after the news that Tom Hanks had contracted COVID-19. As its annual losses had grown, so too had skepticism about Slack’s prospects. Two trading days later, on 16 March, investors knocked the company’s stock down to its lowest­-ever price, 56% below its June debut. They did not yet know that Slack had not only just hit its second simultaneous user milestone in a week but that it would also add almost as many customers in the first seven weeks of the quarter that began Febru­­ary 1 as it had in the previous six months.

The surge in demand didn’t prompt any celebrations at Slack. People were flocking to its product to cope with disaster. Nor was it a time to panic, for the same reason. “People think of Slack like a utility, like Wi-Fi or electricity,” says Henderson, who oversees 700 engineers, one-third of Slack’s staff and the folks charged with keeping the platform running. “It’s a critical service, and it’s always there, always working.”

Slack became part of a moment we will mark for the next hundred years: In March 2020, the global economy changed forever. Work in around the world changed forever. We were reorganized by the coronavirus.

If a company had 6,000 employees, it suddenly had 6,000 workplaces. If work sometimes seemed hard or frustrating to get done with everyone in the same place, now no one was in the same place. A technology like Slack quickly became the sinew that kept the functioning parts of the economy connected. Across industries and geographies, the platform was proving indispensable—­not just to information-­age workers who were already fans but to the scientists scrambling to stop the virus and the people keeping New York City’s subways rolling through the pandemic.

Said CEO Stewart Butterfield on March 20, a week and a day after his earnings call: “You can’t rely on email in this kind of chaos.”

Wickstrom Dairies, located in California, is a 24-hour-a-day, 365-day-a-year operation, built on traditional labor. Its 2,500 cows eat 200,000 pounds of feed a day, 80 pounds per cow, mixed and delivered with front-end loaders and trucks. Wickstrom’s staff milks the cows every day, over the course of 20 hours, and each cow produces about 8 gallons of milk, 21,000 gallons a day.

As the novel coronavirus took aim at California, in March, those 2,500 cows weren’t worried. Cows have been getting their own version of coronaviruses for years (which don’t affect people), and the cows simply get vaccinated. No social distancing required.

But to weather COVID-19, everyone except the cows would need Slack.

Today, there are no pre-shift meetings for the 28 employees at Wickstrom, no small gatherings during breaks, and the staff is spread out—in distance and time. The dairy employees get their assignments on Slack, they see what happened overnight with calves or sick cows, they get the latest news about equipment repairs, and also about COVID-19 itself, all in Slack. “Everyone’s got a phone,” says Aaron Wickstrom, who co-owns and helps manage the family dairy. “Slack has made everybody’s job easier. And safer. Our cows are vitally important, but our people rank higher.”

Meanwhile, 2,900 miles away, tens of thousands of people were falling ill in New York City, the virus’s emerging epicenter. Subway ridership was down 70%, but 1.8 million New Yorkers—healthcare workers, pharmacists, first responders, and others battling the outbreak—still had to get to work. Subways and buses needed to continue running.

By using Slack to gather real-time information about traffic patterns, track conditions, and delays, the city’s Metropolitan Transportation Authority, which as recently as the summer of 2017 had been beset with operational woes, has been able to disperse hundreds of staff members from control rooms and offices to keep them from getting sick. The MTA posts messages and alerts, in real time, directly from Slack to digital information boards in subway stations around the city, and also to Twitter. Employees who would normally be sitting alongside each other in transit operations centers have been able to do their jobs from home, leaving the very few staff essential to operating and monitoring trains extra room to separate themselves. Although the MTA declined to discuss its use of Slack directly, so as not to endorse a particular product, its chief customer officer, Sarah Meyer, wrote the company a thank-you tweet on March 18: “We wouldn’t be able to do this without @SlackHQ.”

Slack is also on the front lines of the coronavirus fight. Nevan Krogan, who runs a lab at UC San Francisco’s Quantitative Biosciences Institute, organized an effort to figure out precisely which proteins in human cells the coronavirus hijacks and uses to replicate itself furiously. If you could map those key proteins, you might be able to find existing medicines—already approved for treating other diseases—that deactivated them, and thus stop COVID-19 from replicating.

Normally, this kind of work would take more than a year. Krogan marshaled 22 labs—some alongside his at UCSF, some in New York and Paris—to divide up the complicated, meticulous, and demanding tasks. He pushed people to get the actual experimental work done in the first half of March, fearing that labs might be shut down by the spread of the virus they were studying. And he was right: Halfway through the effort, UCSF ordered everybody home.

But the work continued. Indeed, it intensified. Mehdi Bouhaddou, a second-year postdoctoral fellow in Krogan’s lab, at one point worked 14 days straight, 16 hours a day, from home.

On Sunday, 22 March, the teams uploaded a paper to the life-­sciences publishing site bioRxiv, outlining 332 relevant proteins and 69 possible pharmaceuticals that might prevent the virus from doing its work. Testing of those medicines against the proteins, against the virus, began immediately at the Mount Sinai hospital complex.

The whole effort took place over Slack. “It was essential,” Bouhaddou says of the platform. This sprawling team of experts was able to stay in touch constantly so that people didn’t make mistakes or drift too far from each other. At all hours of the day and night, the scientists traded questions, insights, theories, techniques, and results. They shared working diagrams to be included in the paper, so everyone could check and adjust them. Bouhaddou says that he sent or read Slack messages every couple of minutes. “It was just like being able to turn to a colleague right there in the lab and say, ‘Am I thinking about this right?’ and get an answer right back,” he says. “Except the colleague was across the city, or in Paris.”

Slack, of course, also runs on Slack, using its own platform to think through problems, procedures, and decisions. But until March, the San Francisco–based company had a work-at-the-office culture.
As the company closed its 18 offices around the world, CEO Butterfield and his top executives made a series of decisions that made Slack’s efforts harder, but its mission clearer. In quick succession, they offered to reimburse each employee up to $500 for whatever equipment they needed to do their jobs at home (monitor, chair, headset); directed everyone not to bother logging sick time, at least through April 15; and when the schools closed, advised people to work when they could—but also to log out and take care of their kids and families—and they’d be paid their full salaries. In a company with 2,000 employees, the Slack message addressing how to manage working from home with kids drew 542 “Slack love” emojis (four hearts stacked two by two in its logo’s colors), 250 double-high-five emojis, 201 Slack-solidarity emojis (raised fist), 158 heart emojis, and 173 emojis with SVP for people Robby Kwok’s face—in all, nearly 1,600 symbols of appreciation.

These moves were a bet, and also a clarifying moment, without being consciously either one of those. If Slack was as indispensable a product as its creators and existing customers insisted, the coronavirus crisis would make that clear. The company had just reported an operating loss of $91.2 million last quarter, but this wasn’t the moment to worry about the cost of a few hundred computer monitors, or whether people would take a sick day without being sick. Slack would take care of its people first during this moment of extraordinary crisis. In turn, those employees would take care of its customers in a similar manner.

Inside Slack, there was no cockiness. Indeed, there was a healthy humility, but also what seemed like a growing confidence in both their ability to handle the strange new world and their ability to help everyone else handle it. With the need for Slack so intense in this moment, the company has brought back something it hasn’t offered in years: 20-­minute, voice-to-voice phone consultations. For free. Any user, free or paid, could schedule time to get help adapting Slack to their needs. The desire for these interactions after two weeks has been so high that senior managers, including Ali Rayl, VP of customer experience and one of the company’s first eight employees, have been doing them.

Hearing customers’ voices, especially in a time of displacement, makes their reliance on Slack vivid. “The increase in interest has really galvanized the company,” says Kwok, the HR chief. The urgency of these customers infuses purpose back into Slack. “A lot of people are relying on us right at this moment,” says CTO Henderson, who’s also Butterfield’s No. 2. “We need the wheels to stay on.”

Slack was never one of those Silicon Valley companies with a messianic narrative, but it has always aspired to become the central nervous system of how work gets done, supplanting email itself. The company has long known that if it can get a team to generate 2,000 messages—about a day’s work for 50 employees, or a week’s worth for a group of 10—they’d be hooked. The company’s customer-­retention rate is well over 90%. So even when the pandemic is over and people go back to an office, the entire notion of a workplace will likely have changed forever. Whether or not the spike impresses Wall Street, in the crisis, Slack is helping make sure that milk gets to stores, that New York’s doctors can get to hospitals, that the world’s scientists can unmask the coronavirus. Says Butterfield, “There’s a feeling inside the company that we were made for this.”

Inside Slack, there was a growing confidence in their ability to handle this strange new world, as well as their ability to help everyone else handle it. 


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