The messaging app that is an acronym for "Searchable Log of All Conversation and Knowledge" was founded by a business of what descent?
Stewart Butterfield Daniel Stewart Butterfield (born Dharma Jeremy Butterfield, 1973) is a Canadian entrepreneur and businessman of Polish descent, best known for being a co-founder of the photo sharing website Flickr and team messaging application Slack.
Luis von Ahn Luis von Ahn (born 19 August 1978) is a Guatemalan entrepreneur and a Consulting Professor in the Computer Science Department at Carnegie Mellon University. He is known as one of the pioneers of crowdsourcing. He is the founder of the company reCAPTCHA, which was sold to Google in 2009, and the co-founder and CEO of Duolingo, a popular language-learning platform.