There seems to be an infinite number of self-destructing apps that promises secure messaging, but Telegram is adding another benefit to its free service - it’s a nonprofit company with an open source model. There are no ads and will never be, plus, anyone can download the sourcecode and read how Telegram works – it’s all available on Github.
The company is from Russia, but it’s not operating comepltely in Russia: Telegram’s servers are spread all over the world and doesn’t even keep encrypted data of any messages labeled secret. Unlike other encrypted email services like Gmail – based on MTProto, Telegram’s encryption originates from the sender’s phone, cannot be forwarded, and can be set to self-destruct on all devices.
You can use Telegram to send cloud-based messages as well, they’re just not going to be secured:
Q: Why not just make all chats ‘secret’?
The important thing to remember is that all Telegram messages are always securely encrypted. The difference between messages in Secret Chats and ordinary Telegram messages is in the encryption type: client-client in case of Secret Chats, client-server/server-client for ordinary chats. This enables your ordinary Telegram messages to be both secure and available in the cloud so that you can access them from any of your devices — which is very useful at times.
The makers of Telegram are also working on encrypted voice calls, but at this time, you can only send texts, images, and videos. Compared to Snapchat, Telegram will allow you to have a group chat with up to 100 users. Keep in mind that your contacts will also need Telegram in order to receive messages.