Slack started working on the app at the end of 2012.

Here, he explains the importance of prioritizing your product’s unique features (and why you can let go of the rest), and shares tips for becoming essential to your customers right away. In this exclusive interview, Butterfield - previously one of the founders of Flickr- reveals how the company’s go-to-market strategy worked like gangbusters. (In fact, they hit those user numbers without a CMO.) So how did the company not only launch with enviable momentum, but so quickly win users' hearts? If there’s one theme that emerges when founder Stewart Butterfield talks about Slack's success, it’s that the company made customer feedback the epicenter of its efforts. And yet Slack hasn’t run any big integrated marketing campaigns - they don't have an elaborate email strategy or buy million-dollar billboards. These tweets are real, and they're the stuff of founders’ dreams. But have you visited its Twitter Wall of Love? And you may have read how the internal-communication platform - now just two years old - is already used by more than 30,000 teams and valued at over $1 billion. You’ve probably heard about Slack’s exponential growth.

Slack founder