The $5bn tech boss who grew up without electricity
The BBC's weekly The Boss series profiles a different business leader from around the world. This week we spoke to Stewart Butterfield, the founder of technology companies Flickr and Slack.
It is not the sort of upbringing you'd associate with one of Silicon Valley's heavyweights.
But Stewart Butterfield spent the first five years of his life living on a commune in remote Canada after his father fled the US to avoid serving in the Vietnam War.
The young Mr Butterfield and his parents lived in a log cabin in a forest in British Columbia, and for three years they had no running water or electricity.
"My parents were definitely hippies," says Mr Butterfield, whose mother and father had named him Dharma. "They wanted to live off the land, but it turns out there was a lot of work involved, so we moved back to the city."
After the family relocated to Victoria, the capital of British Columbia, Mr Butterfield saw his first computer when he was seven, and taught himself to programme from that very young age.
Fast-forward to today and 46-year-old Stewart Butterfield - who founded both photo-sharing website Flickr, and business messaging service Slack - has an estimated personal fortune of $650m (£500m).
But perhaps in part due to his unusual upbringing he says he tries to live frugally.
"In truth I feel guilty spending too much money," he says. "As a Canadian that world seems very strange and alien to me."
Mr Butterfield also puts much of his success down to luck.
More The Boss features, which every week profile a different business leader from around the world:
- 'The day I was diagnosed was the worst of my life'
- The jewellery boss who turned $500 into a $1bn business
- The high school dropout who banked £80m
- 'I found my call in life at that airport'
- 'It's a hacker's paradise out there'
Mr Butterfield says that his seven-year-old self was fascinated by the first wave of personal computers.
"I was around seven in 1980, it must have been an Apple II or IIE that my parents bought," he says. "I taught myself to code using computer magazines."
Mr Butterfield - who changed his first name to Stewart when he was 12 - learned to make basic computer games.
However, he lost interest in computers while at high school, and ended up going on to study philosophy at the University of Victoria. From there he did a masters in the subject at Cambridge University in the UK.
In 1997 he was about to try to become a professor of philosophy when the internet "really started to take off".
"People who knew how to make websites were moving to San Francisco, and I had a bunch of friends who were making twice as much, or three times as much, as what professors were making," he says. "It was new and exciting."
So Mr Stewart decided to give up academia and rekindle his love of computers.
After working as a web designer for several years he launched an online game in 2002 with future Flickr co-founder Caterina Fake, Mr Butterfield's then-wife.
The game - called Game Neverending - failed to take off, and the pair were running out of cash. Frantically looking for a plan B they hit upon the idea of Flickr, going on to build the photo-sharing platform in just three months.
"The first camera phones were also coming out, and more and more households were getting internet connectivity, and then stuff happened so fast," says Mr Butterfield.
Launched in 2004, Flickr was the one of the first websites to allow people to upload, share, tag and comment on photos.
Just a year later the founders sold the firm to internet giant Yahoo for $25m - although Mr Butterfield has since said this was the "wrong decision" as waiting longer could have meant a much bigger deal.
Nevertheless he moved on to bigger things with Slack.
It was 2009 and he and some partners had set up another online game, and again it failed. It did, however, spark a brainwave.
"As we were working on the game we developed a system for internal communication that we really loved," says Mr Butterfield. "We didn't think about it, it was very much in the background. But after a few years we thought maybe other people would like it too."
It formed the basis for Slack, a service that today boasts eight million daily users, three million of whom pay for the more advanced features, and more than 70,000 corporate clients.
Slack enables employees to communicate and collaborate with each other in groups at work, and it has grown rapidly. IBM, Samsung, 21st Century Fox and Marks & Spencer are just a few big names to have signed up. Following a number of investment rounds Slack is now valued at $5.1bn.
Chris Green, a technology analyst at consultancy Bright Bee, says it is rare for an entrepreneur to create something successful out of the ashes of a failed project, and "almost unheard of to do it twice".
"But if you look at Stewart's career, it's not just luck, he's always been innovating in the background and looking for ways to bring order to chaos," says Mr Green.
"That's what Flickr and Slack have both done in their own ways."
Slack does have competitors, though. Microsoft now offers a rival service for free with its Office 365 package, and start-up Zoom boasts a more expansive offering for about the same price.
"There is immense competition from some big well-funded companies so Slack will need to keep evolving," Mr Green says.
Big tech firms have found themselves in the firing line for not paying enough tax - but Mr Butterfield says he would be happy for Slack to pay more taxes.
"I'd also like to see a more equitable tax policy. I have no problem paying tax. I don't think companies are taxed enough, or critically, in the right way."
Regarding the future, Mr Butterfield says that, unlike Flickr, he has no intention of leaving Slack.
"So many things had to go right get to this position - amazing luck was involved - and I am not so smart that I can just make it happen again," he says.
"So if I ever wanted to see how far I could take it, this would definitely be the time to do that."