The other one. No, not WhatsApp. Telegram. It hit 100 million users

Secure messaging app Telegram boasted on Tuesday that it had crossed the 100 million users milestone.

Developers said that Telegram was handling 15 billion messages daily from more than 100,000,000 monthly active users. Around 350,000 more users are signing up every day, it claimed.

Telegram launched as an iOS app in August 2013 before becoming available as an Android version three months later in October 2013. More recently web versions of Telegram and desktop apps for Windows, OS X, and Linux have appeared.

The service, developed by the Russian brothers, provides Snapchat-style self-destruct timers for encrypted messages, group chats, channels and messaging. Back in November Telegram blocked some "public" ISIS-related channels.

Around the same time independent security experts poured scorn of the home-brewed crypto used to build Telegram, saying it was prone to metadata leakage, among other issues. The evident popularity of Telegram could be more down to its slick design and usability rather than its security as a mobile messaging app.

Messaging apps that offer end-to-end encryption such as WhatsApp (on Android, for now) and Apple’s iMessage tend to be preferred by independent security experts.

Pavel Durov founded VKontakte (VK), Russia’s answer to Facebook, before leaving the country and setting up what some describe as a WhatsApp clone with his brother Nikolai. ®