9. Slack

Helping teams communicate better

Stewart Butterfield, co-founder and CEO of Slack
David Paul Morris | Bloomberg | Getty Images
Stewart Butterfield, co-founder and CEO of Slack

Founders: Stewart Butterfield, Eric Costello, Cal Henderson, Serguei Mourachov
Date launched: 2014
Funding: $180 million*
Industry disrupted: Email

If you've ever worked as part of a team, then you know how inefficient and time-consuming email communication can be. Stewart Butterfield, co-founder and CEO of Slack—he was also the founder of photo-sharing platform Flickr before selling it to Yahoo—certainly did. That's why he created a business-app platform that lets people working in teams share data and information easily and from any device they want. Slack can work with a multitude of software services, such as Twitter, Dropbox, GoogleDocs and MailChimp, to name a few.

Basically, Slack allows users to consolidate, organize and archive the ever-growing reams of data that modern-day work teams have to contend with. Using its proprietary software, Slack pulls all these disjointed electronic conversations together into a single, searchable and organized view and gives teams more visibility into what everyone is doing, in turn creating one search box over nearly every service the team uses. There's a free version of Slack, but the company makes money with the paid version, which costs $6.67 per month per user and offers enhanced features and priority support services.


Since its launch in February 2014, the company has raised an impressive $180 million from investors, including Accel Partners and Andreessen Horowitz. It claims 500,000 daily users across more than 60,000 teams. Customers include Wal-Mart, Comcast, the New York Times and many start-ups.

*UPDATE: Funding level as of March 1, 2015, the date we closed the nomination process for the 2015 CNBC Disruptor 50. Slack closed an additional round of funding on April 16, bringing its total as of publication to $340 million.

"Slack was inspired by a set of tools and practices we developed while working on a totally different project. We eventually realized we didn’t want to work anywhere that didn’t have this sort of platform in place, so we started from scratch and built it the right way." -Stewart Butterfield, Slack CEO

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