Slack co-founder and CEO Stewart Butterfield.
Slack co-founder and CEO Stewart Butterfield. - 
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Slack has been called an email killer. It's a tool that can generate so much new conversation inside companies, some old-school managers might raise an eyebrow at how much work is, in fact, getting done. But one thing is certain: the company that's changing how we work is itself being rapidly transformed. Not least by money. After raising $160 million this Spring, the company is valued at $2.8 billion. And the customers using Slack, initially heavy on tech startups, have grown to include Fortune 500 companies. 

"It does change what we’re thinking about," said CEO and cofounder Stewart Butterfield. "When we first started working on it, there was a team of 8. And after the first three months or so, we had developed the perfect internal communication software for exactly 8 people. And it took us a little while to figure out how that broke down at 50 people, and how that broke down at 100 people."

Customers use Slack in surprising ways:

There’s all kinds of little ones. So mostly the kind of information that they post into the channels. Whether that’s the election results as they’re coming in so that all the journalists covering an election have the latest stats. Or, in a shipping and logistics company, new deliveries at the warehouse. So it’s not surprising in the sense that we could never have imagined any of those things, but it is surprising in the sense of just, you know, the range of possible types of information that people need to distribute and be aware of on a day-to-day basis across different industries.

On the possibility of being acquired:

We are staying away from that right now. There’s four cofounders here, all of whom were on the original Flickr team, and so all of whom went to Yahoo when Yahoo acquired Flickr in 2005, and worked through that for several years. So I guess we feel like we’ve done that already. I think we’re also conscious that we’re not going to get an opportunity of this magnitude again over the course of lives. It’s fun to work on it and see how far we can take it.

But has Microsoft, in particular, come knocking?

 I guess it depends on how you define ‘try to buy.’ But I’m sure that there’s some strategic interests.

His greatest fear:

It’s the people. We were at Christmastime, last Christmas, and we were 80 people, and now it’s 250. And that’s obviously a lot of growth. That means we ended up with teams that were two people now are eight people, but 75 percent of that team has been at the company for less than 90 days. It’s really difficult to preserve both the understanding of the mission and what we’re doing, preservation of the culture, but also just to try to maintain the same level of productivity or efficiency. Because as we grow, every process we develop becomes obsoleted within 45 days of getting it nice and smooth. So it’s hard to grow this fast.

 Editor's note: We use Slack at Marketplace at no charge; a courtesy they extend to nonprofits. 


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