The company’s growth — it now has more than 900 million users — has been driven partly by a commitment to free speech. As word spread online over the weekend, news of his detention became a flashpoint in a continuing debate about free speech on the internet. In March, Mr. Durov told The Financial Times that Telegram was nearing profitability and considering an initial public offering. Reports of Mr. Durov’s arrest were immediately met with criticism by fans of the service as an example of governments trying to censor free speech on the internet. Although Mr. Durov portrays himself as a crusader for free speech, many security experts have said Telegram is not sufficiently encrypted.
