Slack

In 2014, as Slack officially launched, Stuart Butterfield was already dissatisfied. When asked by MIT Technology Review if they were working to improve Slack, he responded bluntly: "I feel like what we have right now is just a giant piece of shit. It's just terrible and we should be humiliated that we offer this to the public." This wasn't cynicism—it was a philosophy. Stuart believed that if you couldn't see "almost limitless opportunities to improve," you shouldn't be designing the product. This relentless dissatisfaction became a cultural cornerstone, printed on office walls and repeated at company all-hands as a rallying cry for continuous improvement.

Slack wasn't the first team messaging app, but it was built with an obsessive focus on what Stuart called "tilting your umbrella"—the small acts of courtesy and empathy that create emotional connections. One early insight came during a walk in Vancouver with creative director Brandon Velasco. They noticed how few people with umbrellas would move them out of the way on narrow sidewalks, poking others in the eye. They realized most people either didn't notice their impact or didn't know how to solve it. This became Slack's north star: "Your failure to consider and exercise courtesy and be empathic about other people's experience is an advantage you can create."

This philosophy manifested in specific design choices. Rather than forcing users to enter complex passwords on mobile, Slack pioneered the "magic link" experience—send a link via email that automatically authenticates you in the app. When Slack realized new users expected notifications for every message (from their experience with SMS and instant messaging), the team struggled with the default. They eventually set notifications to "on" for new accounts, but after 10 messages, a gentle prompt suggested better settings. Most importantly, they developed the "shouty rooster"—when you tried to @everyone in a channel, a rooster would appear asking if you really wanted to notify 147 people across 8 time zones. These small moments of friction-as-a-feature shaped behavior without making users feel stupid.

Slack's growth came primarily through word-of-mouth and organic cross-pollination. An engineer at a startup would discover Slack, evangelize it to their team, then move to another company and bring the enthusiasm with them. This created a network effect without heavy marketing. Users formed genuine emotional connections to the product, not just because it was functional but because it delighted them—the copy was clever, the experience felt refined, small details suggested someone cared.

Stuart's vision for B2B SaaS was countercultural at the time. Most enterprise software prioritized features and speed; Slack prioritized taste and craft. This gave them a critical advantage, especially in recruiting evangelists who would carry their preferences to new organizations.

Stuart's concept of "utility curves" guided all product decisions. Rather than thinking of features as binary (have it or don't), he visualized an S-curve where effort on the x-axis maps to value on the y-axis. The key insight: there's a threshold where small investments yield no value, then a steep part where investment pays off, then diminishing returns. A hammer handle that breaks is useless; one that's barely stronger is still junk. But beyond a certain quality threshold, more investment doesn't matter. This prevented Slack from over-engineering features or building things that weren't good enough to matter.

Another core principle was the distinction between friction and comprehension. While conventional wisdom said to always remove friction, Stuart argued that friction is often needed when the real challenge is helping people understand what something does. At Slack.com, visitors had minimal intent and low specificity about what they needed. Reducing steps would only help if they knew what they were aiming for. What they needed was clarity: "What is this thing and what am I supposed to do next?" This led to detailed onboarding, clear visual hierarchy, and a philosophy of "don't make me think." Every unexplained option burned glucose and made users feel stupid.

One elaborate example was the rollout of "Do Not Disturb." With millions of users across thousands of organizations, Slack couldn't just enable it globally. Instead, they created a system where organization admins received advance notice, a sensible default was set (7 p.m. to 7 a.m. or 8 a.m. to 8 p.m. in local time), admins could override it, users could override the admin setting, and admins could override users again. This complexity was justified because it prevented conflict and ensured people actually used the feature rather than disabling it immediately.

Slack's success—built on taste, empathy, and obsessive attention to detail—eventually caught the attention of Salesforce, which acquired the company for $27.7 billion in December 2020. Stuart left Salesforce two and a half years after the acquisition, coincidentally three days after his daughter was born. Today, he spends time with family, works on philanthropic projects, and supports other artists and creative endeavors. He's been approached every three to six weeks with ideas for a new company, often with Cal Henderson, the CTO and co-founder he's worked alongside for 23 years since their Flickr days. But he's cautious about what's next, concerned that technology in its current form might be "destroying the world." His legacy at Slack endures: a reminder that in B2B SaaS, the margin created by your competitors' failure to care about craft and human experience is precisely your opportunity.