Communication is fundamental to human beings. Yet it’s rare that a company changes how we connect and work together, much less how we delight one another. (With emoji or otherwise). Slack has somehow managed to do just that. It’s made work more fun for millions of people.

In the process, it’s made work so much better, as well.

What Stewart, Cal, and the Slack team have accomplished is more than remarkable. It’s invaluable. With no hyperbole, their achievement is simply life-changing. The pivot from Glitch to Slack by now may be a familiar tale, but let’s not forget just how much courage, vision, and bull’s-eye execution it required. Pivots rarely pan out. The fact that this one found lasting success owes to the founders’ extraordinary foresight and entrepreneurial grit.

Slack holds a special place in our hearts and in our own firms’s history. It is literally where three Kleiner Perkins partners (Mamoon Hamid, John Doerr, and Ilya Fushman) first worked together. That collaboration became the basis of our partnership at Kleiner Perkins today.

The three of us led the first three investment rounds for Slack after its relaunch in February, 2014, as an enterprise messaging company. With its cross-platform app that displaced email, iMessage, Gchat, and other modes of workflows, Slack caught lightning in a bottle. It gathered in one place all of your transmissions with colleagues on any device, from anywhere, at any time. With hindsight this might seem simple and obvious, but many had tried to do it before and failed. By wrapping human communication, signals from critical apps, and a high-powered platform into a single, unified, playfully magical experience, Slack captured the hearts and minds of knowledge workers around the world.

In April 2014, when Mamoon was at Social Capital, he invested in Slack on the basis of off-the-charts engagement (DAU/MAU) and free-to-paid conversion on a relatively small number of users (50,000 DAU) and under $1 million of ARR. That October, on the basis of 5x growth in less than six months, John led the next round for Kleiner Perkins. As Slack built out its team, Stewart and Cal considered bringing in Ilya, then Head of Product at Dropbox, to lead their product team. Ilya opted instead to join Index Ventures, and quickly led another round in April, 2015. That was an eventful 12 months, to say the least–unprecedented, whirlwind growth together with pedal-to-the-metal fundraising. Best of all: The customer love for Slack was passionate and enduring.

Work is increasingly complex, distributed, and fast-paced. To live fully, we need to cut through the noise, simplify teamwork, and get our work done swiftly and efficiently. Few companies have effectively grappled with this challenge. Fewer still have had such outsize, everyday impact. That’s what makes Slack the most important software in our lives.

Making work happen is best done together, and we want to congratulate the entire Slack team on joining forces with Salesforce.

ー Mamoon, John and Ilya