Marc Andreessen (a Pando investor) just tweeted this chart of Slack’s “viral” growth.

Screen Shot 2014-08-13 at 12.42.29 PM

Let’s acknowledge that there’s a lot of data missing from this. Like churn rate, for one. Still, for an enterprise app, it’s impressive. And it’s even more impressive given the backstory of Slack.

It was founded by Stewart Butterfield, former co-founder of Flickr. Both Slack and Flickr grew out of failed attempts to build a gaming company, as Carmel D’Amicis detailed in her excellent in depth profile written just as Slack started taking off.

From that piece:

But between Butterfield’s big triumphs were hard times, namely his attempts and failures — twice — to build a “never ending” game. He wanted to create a gaming world where people didn’t go to win. They went to play forever. He wanted to build a culture and community online.

Butterfield wanted to create this game so badly that when it failed the first time — in the early 2000’s — he couldn’t let it go and returned to it again in 2009 after his hit with Flickr. Ironically, both Flickr and his current project Slack were pivots spun from infrastructure built to support the game creation process. And both have seen far greater success than his beloved game ever did.

Butterfield’s story is one many entrepreneurs can identify with. It’s a tale of risk taking, passion, perseverance, and success. But it’s also one of fear, failure, and disappointment. It’s rare in Silicon Valley that a product could flop so hard — not once, but twice — and yet out of that failure could come — not one, but two — hits.

Looking at the struggles of Zynga and now King, Butterfield should be thrilled he’s such a “failure” as a gaming exec. He may actually build a huge company that people love for more than five minutes.