The Slack staff knew about this effort, and whether it was the program, the celebrities, or it being a Thursday afternoon—the slot in the week when Slack hosts “gather hour,” its more inclusive, less drunk spin on happy hour—the room felt like a high-school auditorium before a pep rally. The celebrities appeared and a raucous wave of applause overtook the crowd as Legend, Leal, the comedian Robin Thede, and Slack’s CEO, Stewart Butterfield, took the stage.

Butterfield is small in stature, with brownish-reddish hair and glasses. His shirt read We Are All Dreamers. If you’re used to Elon Musk’s bombast, Mark Zuckerberg’s cheery will to power, or even garden-variety start-up boosterism, Butterfield is refreshing and strange, having retained some of that ’90s internet funk. He is the kombucha of tech CEOs.

Like a good CEO, he began by thanking the partners in the program. They beamed from the front row: Chris Redlitz and Beverly Parenti, the founders of The Last Mile; along with Kellog’s contingent, CEO La June Montgomery Tabron and the grant maker Cynthia Muller. (Legend’s criminal-justice-reform organization, Free America, is also on board.)

But before the celebration could even get underway, Butterfield said, “The bigger issue is bigger than us and the things we’ll be talking about today.” He described seeing Bryan Stevenson, the founder of the Equal Justice Initiative and the author of Just Mercy, and being changed by him. “Holy shit, he’s a powerful, powerful speaker,” he said. “That was the year that everyone got Just Mercy as a Christmas present.” That was two and a half years ago. Butterfield visited The Last Mile at San Quentin and came away thinking Slack could make a difference working with them.

Now more than 100 Slack employees have visited San Quentin to meet and mentor people enrolled in The Last Mile’s coding program. And Butterfield offered up his company as the test case for getting prison-trained coders into high-growth start-ups, something that has not really worked yet.

“I don’t want to say this is it. This is a very experimental approach and obviously we hope the experiments work,” he said. “But even to the extent we are successful, which is providing pretty amazing opportunities for a relatively small number of people, we need to create a larger number of opportunities for people. I say we, but I mean us, the country.”

More than 20 percent of the whole world’s prison population is sitting in U.S. jails and prisons, even though Americans make up only 5 percent of the world’s population. The country, I mean us, has been terrible at providing opportunities for people leaving prison. The formerly incarcerated are five times more likely to be unemployed than the general population. Things are especially bad for black men, who experience significantly higher unemployment than white men leaving prison.