Pavel Durov

He’s been called the “Mark Zuckerberg of Russia,” but it’s time to ditch the epithet and recognize Durov’s achievements in their own right. After having his Facebook clone, VKontakte, the second-most-popular website in Russia, ripped away from him by alleged Kremlin cronies in 2014, Durov focused his efforts on Telegram. The encrypted-chat app has amassed more than 200 million monthly active users since its founding five years ago. It has even hosted one of the most extravagant “initial coin offerings” to date, raising a reported $1.7 billion in exchange for promised crypto coins. Now Durov, a newly minted billionaire, is fighting bans in Russia and Iran, where government leaders claim Telegram facilitates insurrection. (Also see No. 25 on the main Fortune 40 Under 40 list.)