76. Brian Acton
Whatsapp’s cofounder announced in September that he is leaving the messaging service he cofounded with Jan Koum (No. 48) 8 years ago. Acton said he will be starting a nonprofit. He applied for a job at Facebook but was turned down in 2009, the same year he helped start Whatsapp. Five years later the social network paid $22 billion in cash and stock for the company, which now has 1 billion daily users, who send 55 billion messages on the platform each day. Acton and Koum worked together at Yahoo.