In a conference room at the back of his Vancouver offices, past the bright faux-grass wall, elegant canopies covering a couple of meeting spaces, and a dozen busy young staffers standing in front of raised workstations, Stewart Butterfield is picking at his takeout lunch from a local Japanese joint, running through a quick history of Japanese emigration to Vancouver that culminates in a passionate recommendation of his favorite yakitori spot. He especially loves their chicken hearts. "They are to dark meat as dark meat is to white meat," he says. "It’s simply more intense."
Butterfield—who runs the hottest business-software startup to come along in, oh, forever—is far more philosophical, ruminative, and entertaining than your typical CEO. Over the course of two days, our discussions ramble through topics such as contemporary academic philosophy, Phish, mergers and acquisitions, McDonald’s, the dilemma of constraints and possibilities as reflected in software design and Christian Bök’s Eunoia (a novel with five chapters, each of which uses a single vowel), constipation, Mark Zuckerberg, addictive sex, and librarians. And, yes, poultry. "I am suspicious of anyone who prefers white meat," he muses, grinning at his own gall. "They’re self-deluded. It’s simply impossible to prefer the texture or the flavor."
Butterfield feels the same way about Slack, his messaging/group chat/document-sharing application: It is impossible for him to imagine anyone preferring email or other traditional modes of office communication. Launched in late 2013, Slack has already attracted 1.25 million daily active users at hundreds of companies, including Comcast, Dow Jones, Expedia, Blue Bottle Coffee, Intuit, Zappos, and even NASA. According to the company, 800 million Slack messages were sent in July—up from 290 million in January—and there are currently 10 times as many users as there were a year ago. Customers seem to find it more useful, engaging, and just plain fun than any prior communication tool. Venture capitalists have noted that passion, backing Slack with $340 million (the company is currently valued at $2.8 billion). That’s a heck of a lot of money for a startup that’s just two years old, lacks a sales force, and is trying to take on Microsoft in the hypercompetitive market for enterprise software. For all of its buzz, the company has a long way to go before it poses a serious challenge to the industry’s long-dominant players.
But if Slack continues to have this kind of impact, it could redefine the way we communicate at work. Using the software, much of a company’s interaction takes place in lively group-chat "channels," which replace those endless reply-all email chains that have become a bane of modern corporate life. To share something, you simply post to the channel, rather than CC’ing a select group. If you need to alert someone specific, you can type her user name with an "@," à la Twitter, or send her a direct message. Slack syncs everything across smartphones, tablets, laptops, and desktop computers that are tied into that network.
The experience feels fundamentally different—more contemporary, more in tune with people’s out-of-office digital lives—from what we have experienced for 20 years, closer to social media than old-fashioned email drudgery. Slack isn’t just another office tool: It’s a welcoming environment where employees (virtually) live. That’s a big shift, enabled by and concealed in the app’s thoughtful, quiet, and inviting design. Slack’s look and interface aren’t showy. Everything seems natural, and everything seems to work the way you’d expect it to. Slack is taking off not because it screams its ambition to replace your current work tools, but for a more profound reason: It wants to be your friend.
The night before our office lunch I meet Butterfield at Vij’s, a local Indian spot where he has been a regular for the past 16 years. Butterfield has spent most of his working life in Vancouver, just a three-hour drive from Microsoft’s headquarters in Redmond, Washington. The vibe at Vij’s reflects the fact that tech hubs are emerging all over the world—there’s a feeling of young, smart wealth here, but also a Canadian restraint that’s quite different from Silicon Valley flash.
Butterfield has never followed any obvious path to tech stardom, and that idiosyncratic journey is crucial to the Slack story. The software is a direct reflection of the unique personality that shaped it. Butterfield was born in the backwoods of Canada in 1973 to a hippie-ish mother and a draft-dodging father, who lived in a log cabin and named their baby boy Dharma Jeremy Butterfield. It wasn’t until he was 12 that his parents, who by that time had made the psychic and literal move to the city of Victoria, British Columbia, and had successful careers in real estate, let him legally change it to Stewart.
When he was 7 years old, Butterfield got his first computer, and while he loved playing video games, he was hardly a traditional tech geek. In his studies he was drawn to philosophy, and at the U.K.’s Clare College, Cambridge, he wrote his thesis on "the difference between living things and nonliving things," he says. "And guess what? The answer is that living things are alive! It took me 30,000 words to get that across."
In the late 1990s, Butterfield moved to Vancouver, and in 2002 he and his then-wife, Caterina Fake, decided to launch a company to build their own MMO game, called Game Neverending. It was as quirky as its founders—and a financial flop. In 2004, Butterfield, Fake, and an employee decided to use the image-sharing technology that they’d created for the game to launch something they named Flickr. The pioneering photo-sharing website presaged much of what was to come in the world of social media, and was a fast success. They sold it to Yahoo in 2005, for around $25 million.
As part of the sale, Butterfield became a Yahoo employee—a three-year ordeal that proved instructive. "It was mind-blowing," Butterfield says. "I’d never worked in a big company. All the software was terrible. The payroll, time-tracking, benefits, intranet, even the 401(k) was designed in a weirdly bad way." Butterfield eventually quit to launch another game, called Glitch. It, too, went nowhere. But when they were developing the game, he and his crew of programmers had come up with a cool way to collaborate on their company’s little network. Seeing the chance to create a work environment that was a million times better than what he had suffered through at Yahoo, Butterfield transformed that program into what would become Slack. The new company launched in December 2012, with a total staff of just eight people.
From the beginning, Butterfield designed Slack for end users like himself, rather than first considering the needs of corporations or the demands of IT managers, which is how most enterprise software is created. As a result, Slack—unlike predecessors such as HipChat and Yammer—is a triumph of humane thinking.
"We’re really conscious of solving problems in a way that doesn’t fetishize the purity of UI design at the expense of the user," says Slack’s design director, Brandon Velestuk, who has worked closely with Butterfield since joining Slack in 2014. "There was always an understanding that this was a tool people were going to spend their entire day in, so we sought to bring an empathy to the design."
Slack’s in-app communications are intended to reinforce the idea it’s designed for you, a regular human being, by other normal people. When you log in for the first time, a dialog box pops up to say, "Hello. Thank you for signing up for Slack. We’re really happy to have you!" In the morning, you might be greeted with cute little phrases such as, "Please enjoy Slack responsibly."
"Slack’s tone might not be a benefit for every kind of company," Butterfield acknowledges. "But even people who work in the most boring parts of the most boring accounting firms are still human beings. Some of them still go home and smoke weed, for example—not that smoking weed is the hallmark of humanity."
It’s a voice that sounds, not coincidentally, a lot like Butterfield’s. "I used to respond to every tweet myself," he says. "That tone was established by, oh, 15,000 tweets. There’s a very particular place we want to be in people’s minds: not too boring and stodgy, but never slapstick. We want it to be relatable—genuine, respectful. One of my favorite tweets—something we’ll do every once in a while—is, ‘Absolutely!’ with the exclamation mark." He laughs, but there’s a hint of pride not far from the surface. "I consider that my masterpiece."
That approach helps explain why at many companies Slack has been introduced not by IT managers, but by regular employees who have heard about the software from friends or have used it elsewhere. Slack came to Zappos, for instance, via a developer who started using it with his team. Seeing how much they enjoyed the experience, collaboration product manager David Fong started rolling it out to anyone who wanted it. So far, about two-thirds of Zappos’s 1,400 employees have elected to get Slack on their computers. "It feels right to so many people," Fong says. "Zappos is very focused on culture, and Slack is a fun user experience. It’s like, if you go to work in a drab, colorless building, work can feel sterile. Slack isn’t sterile."
As the waiter at Vij’s wraps up our leftover lamb popsicles and vegetable koftes for Butterfield to take home, Slack’s CEO is laying out his ambitious plans for his company’s future. "Replacing [Microsoft’s] Exchange Server as the essential hub where all the information flows, I think that’s something we’ll do very well," he says. "We can be the bottom layer of the technology stack, and make everything else better." Thanks to adoring word-of-mouth and increased media attention, Slack’s public profile grows every day. Revenues—some companies pay fees of up to $15 per user per month, depending on the level of security and services—are closing in on expenses, and should accelerate after Slack introduces a more robust and expensive "Enterprise" version later this year.
In order to deliver on Slack’s potential—and justify that high valuation—Butterfield and Co. must now convince corporate America that it is truly an indispensable product. The first step is to merge Slack with every other crucial piece of software on a corporate network. Slack is in the process of creating integrations for a slew of products from a wide range of third-party vendors. Twitter, Box, Dropbox, Stripe, and Google products such as Drive and Calendar are already integrated, along with dozens of other apps. One particular workplace favorite is Giphy, which lets users post random GIFs into conversations (try to find that in your Outlook). According to Butterfield, more than 400 companies are waiting for Slack to integrate their applications.
Still, Slack has to clear some major hurdles before it can become a truly significant player, and getting old-line companies on board is going to be challenging. The company’s early customer base has primarily been startups and media companies, which tend to have simpler structures and, crucially, less-stringent security standards—a huge area of concern for enterprises of serious scale. While Zappos’s Fong loves Slack, he won’t allow it to be used for anything that’s customer-related or financial. That wariness was reflected by other IT managers I spoke with, most of whom rely on Microsoft products. "I like Slack’s ease of use; I like the file sharing and the searchability," says the head of technology at one New York investment group. "But in its current format, Slack is unlikely to find traction in a firm like ours. As things stand, my impression is of a fuzzy, feel-good millennial hipster tool rather than a buttoned-down, conservative, and justifiable platform." While he’s open to reexamining Slack in the future, he’s skeptical. "No one ever got fired from an IT department for buying from Redmond," he says. Ask Microsoft about Butterfield’s ambitions and the response is diplomatic but dubious. "When you have 1 million, 2 million [overall] users, there’s one set of requirements," says Julia White, GM of product marketing for Office at Microsoft. "But then when you go big, there’s a whole new set of requirements." According to White, one out of every seven people on the planet uses Office.
Garnering tens of millions of corporate users as an independent company could be hard for this and many other reasons. But Slack might be an attractive takeover target or strategic partner for a bigger company. Butterfield swears he isn’t interested in selling. "M&A generally doesn’t work," he says, alluding to his experience with Flickr, which, since the Yahoo acquisition, has been overshadowed by newer photo services like Instagram. "The special culture is crushed, the pace of innovation is slowed." He also admits that this is exactly what he’d say if he was, in fact, trying to sell the company.
Whatever happens to Slack, there’s a decent chance that Butterfield and Velestuk will be remembered as the guys who finally vanquished email, which, after 20 years, is starting to feel as stale as pneumatic tubes once did. "I could talk to my kids about it and say, ‘Well, there was this thing called email back in the day. I used it quite a lot . . . ,’ " says Velestuk. "That would be pretty nice."
A version of this article appeared in the October 2015 issue of Fast Company magazine.