Ukrainian Developer Built a $19.3 Billion App — Because Silicon Valley Was Too Ignorant to Do It

33-year-old Jan Koum capitalized on Silicon Valley’s blind spot and built the world’s largest messaging platform with $0 ad spend

WhatsApp CEO Jan Koum speaking at the Mobile World Congress on February 24, 2014, Barcelona, Spain. Shutterstock image

“I did 9 years at Yahoo.”