Telegram was created by "Nikolai and Pavel Durov, the founders of VK, Russia's largest social network." Some background on this is available in this CNBC story:
Then the Kremlin tightened its grip over the Internet and President Vladimir V. Putin's allies took control of VKontakte. Mr. Durov eventually sold his remaining stake for millions and fled Russia in April, after resisting government pressure to release the data of Ukrainian protest leaders.
As the tensions in Russia play out, Mr. Durov says he is focused on Telegram, which he started last year. There will be no outside investors, he says, no ads and no marketing, and it is available free, though he is likely to eventually charge for additional services. He says he has about 50 million users, almost entirely outside Russia.
Telegram is competing in a crowded field of messaging apps that promise varying degrees of security. Telegram has its fans and detractors, but it was rated respectably in a recent evaluation by the Electronic Frontier Foundation. The Telegram company, based in Berlin, has a deliberately complex structure of scattered global shell companies intended to keep it a step ahead of subpoenas from any one government.
I have no connection with Telegram other than the fact that I just signed up for an account. As usual, I did so partly to camp out on my username (@Randomness).