Crowds marched through Moscow on Monday, firing paper planes and calling the authorities to unblock Telegram.
"Putin's regime declared war on the Internet, declared war on free society... so we have to be here to support of Telegram," a protester told Reuters news agency.
"You make me excited and proud to be Russian", Pavel Durov wrote on Twitter. On VK, the "Russian Facebook", Durov welcomed it: "Thousands of young and progressive people are now protesting in defence of internet freedom in Moscow - this is unprecedented". "Your energy is changing the world."