Stewart Butterfield (born Daniel Stewart Butterfield in 1973) is a Canadian-born entrepreneur and businessman, best known for being a co-founder of the photo sharing website Flickr and team messaging application Slack.
Butterfield was educated at St. Michaels University School in Victoria, British Columbia. He received a B.A. degree in philosophy from the University of Victoria in 1996. Butterfield went on to earn a Master of Philosophy from the University of Cambridge in 1998, where he specialized in the philosophy of biology, cognitive science, and the philosophy of mind.
In the summer of 2002, he co-founded Ludicorp in Vancouver with Caterina Fake and Jason Classon. Ludicorp initially developed a massively multiplayer online role-playing game called Game Neverending. The game did not launch, but the company then started a photo sharing website called Flickr. In March 2005 Ludicorp was acquired by Yahoo!, where Butterfield continued as the General Manager of Flickr until he left Yahoo on July 12, 2008.