Stewart Butterfield

Stewart Butterfield is a Canadian technology entrepreneur and angel investor who co-founded Flickr (2004) and Slack (2013) — two landmark products that emerged as accidental pivots from failed multiplayer games. A self-taught coder with a Cambridge philosophy degree, Butterfield sold Flickr to Yahoo for ~$25 million in 2005 and Slack to Salesforce for $27.7 billion in 2021. His 'We Don't Sell Saddles Here' memo became a canonical document in Silicon Valley product thinking. Since departing Slack in January 2023, he has been active as an angel investor with 32+ portfolio companies.