Stewart Butterfield has failed spectacularly twice, and become extraordinarily rich from both failures.
The first time: in 2002, his gaming startup Game Neverending needed to survive. They pivoted the photo-sharing tool they'd built internally for the game into a standalone product. That product was Flickr. Yahoo acquired it in 2005 for a reported $22–$25 million.
The second time: in 2012, Butterfield's new company Glitch — a massively multiplayer online game with an elaborate world built on the idea of cooperative creativity rather than combat — shut down after six years and $17.5 million in funding. Players loved it. Not enough of them, and not enough to build a business. Butterfield announced the shutdown with characteristic grace, refunding unspent purchases and writing employees individual thank-you notes.
While building Glitch, the team had needed a way to communicate internally across four offices in different time zones. Email wasn't working. IRC was too technical for everyone. They built their own internal messaging system — something that could handle text, files, search, and notification management in one place. It worked so well that when Glitch died, the messaging tool was the only thing worth keeping.
Building a Product From the Corpse of a Game
Butterfield raised $1.5 million from investors in August 2013 specifically to turn the internal messaging tool into a commercial product. He'd seen what the tool did for his team's coordination. He believed enterprise communication was genuinely broken — that email threads lost information, that important decisions were buried in inbox noise, that search across organizational knowledge was essentially impossible.
The tool was designed around three core ideas: persistence (every message searchable forever), channels (organized conversation streams rather than email chains), and integration (connections to every other tool a team uses). These weren't new ideas individually. Pulling them together in a consumer-grade interface aimed at people who had never used IRC was new.
The Name
The internal project needed a name. The team considered various options — something that conveyed speed, looseness, ease. The word "slack" emerged, and it stuck before anyone interrogated it too closely.
Someone in the team later noticed that the letters spelled an acronym: Searchable Log of All Conversation and Knowledge. Butterfield has confirmed this in interviews — the acronym was discovered after the name was chosen, not before. The name came first; the backronym was assembled afterward.
Whether the backronym is taken seriously as a description or just used as a marketing explanation depends on who you ask. The "searchable log" framing is genuinely accurate to what the product does: everything typed in Slack is searchable, retained, and theoretically organizational knowledge. But it was clearly reverse-engineered from the word, not the other way around.
A backronym (backward acronym) is a phrase constructed to fit a pre-existing word or abbreviation. SOS famously doesn't stand for anything — it was chosen because the Morse code pattern (three dots, three dashes, three dots) was easy to transmit. "Save Our Souls" came later, as explanation rather than origin. Slack joins a long list of brand acronyms where the letters were made to fit after the word was chosen.
Growth That Broke Records
Slack launched publicly in August 2013. It added 8,000 users on day one. Within 24 hours, it had 15,000 registered users. Within 2 weeks, 30,000. The phrase "fastest-growing business application ever" gets attached to Slack frequently, and the early growth data supports it: $0 to $7.1 million in annual recurring revenue in the first year, $38 million in the second, $230 million in the third.
The growth happened primarily through word of mouth among developers and tech workers who recognized immediately what the product replaced. By the time enterprise companies started taking notice, Slack was already deeply embedded in the teams doing the actual work.
Salesforce acquired Slack in July 2021 for $27.7 billion — the largest acquisition in Salesforce's history. Butterfield stayed on for a period and then departed. The product continues to operate as a largely independent unit within the Salesforce ecosystem.
The Design That Everyone Notices
Slack's visual identity — particularly the hashtag logo — was designed by Michael Evenson, Slack's first designer, and later refined by the firm Pentagram. The original logo used a pinwheel-like arrangement of speech bubbles. The Pentagram redesign introduced the simplified eleven-color hashtag mark (twelve segments, each at a precise angle, in a carefully selected palette).
The color choices were deliberate: the logo uses four colors (aubergine, green, yellow, red), each applied to two of the four "arms" of the hash symbol, creating a small but distinct color-recognition challenge. Pentagram noted that the logo had to work against any background color that might appear in the app's variable interface — a constraint that shaped the final design significantly.
Trademark Note
Slack Technologies, LLC (a Salesforce company) holds U.S. trademark registrations for "Slack" and the hashtag/pinwheel design mark across multiple classes including Class 38 (communications software and services) and Class 42 (SaaS, computer services). The mark has been in continuous commercial use since 2013. Salesforce's acquisition transferred the trademark portfolio, though Slack operates under its own brand identity. The registration covers both the word mark and the specific hashtag design configuration — the eleven-color arrangement is distinctive enough to qualify as a design mark in its own right.