A self-professed introvert, which is fitting for a company that sells itself on textual communication, he values efficiency and candour. After Yahoo bought Flickr, he worked there for a few years. “Everything was horrible, ugly, slow, difficult to use and confusing,” he says, frankly.
In retrospect, Flickr was sold too soon. The sale marked the beginning of the technology industry's resurgence after its crash in the early 2000s. Now Mr Butterfield has a second chance. Investors do not want to see him sell Slack too early. Earlier this year there were reports that Microsoft considered bidding around $8 billion for the company. Mr Butterfield says that Slack has never received a formal offer from anyone and is planning to go public. Last year it started submitting itself to voluntary audits, in what appears to be preparation for a public debut. But it seems even more likely that a large tech giant will see the strategic value of Slack and try to snap it up first for an even splashier sum.
Mr Butterfield says that Slack could achieve $10 billion in revenue if it signs up 100m knowledge workers, of which there are around 850m worldwide. That is far easier said than done. For one thing, Slack still needs to woo larger companies outside the technology world. Currently it holds particular appeal among workers at firms in the internet, media and advertising industries, and among teams of software developers within larger firms. Conquering traditional businesses may prove harder. Slack's yearly minimum of $80 per employee is steep for companies with tens of thousands of workers.
For another, Slack has rising competition to fend off. Already, rival products are taking aim at the market for workplace collaboration, including one, Atlassian, from an Australian software company, which is called HipChat, and bundled with its other services. There is also Symphony, a rival startup backed by several banks that specialises in highly regulated industries such as financial services, which require more compliance controls. Tech giants such as Microsoft, Oracle and Facebook have collaborative work apps, but these are only modestly successful.
Slack's greatest challenge may be people's own habits. To some, its endless stream of chatter may be worse even than e-mail, because the barriers to commenting rapidly are lower. The introverted Mr Butterfield should welcome the chance to appeal to people who do not want constant interaction, even when it comes in textual form.