This is a really bad idea because the chatting is not decentralized. There's a centralized chat server which costs real USD $ to keep operating. This looks like one of the worst investments I've ever seen on bitcointalk.
They're using APIs. A highschool student could build this in their basement over summer break for 20 BTC.
This is really so dumb... what's the plan once funds run out and you can't host a centralized chat server?
I would rather see some sort of chat app that uses the blockchain to store messages for a short time period and then deletes them. This would create a sustainable product. Instead of have some garbage that will flop hard. It's funny... if the app gets popular, it will fail because it needs to expand with more centralized servers.
That's possible with SendChat: It's called secret chat
Secret chats are meant for people who want more secrecy than the average fella. All messages in secret chats use end-to-end encryption. This means only you and the recipient can read those messages — nobody else can decipher them, including us here at SendChat. Messages cannot be forwarded from secret chats. And when you delete messages on your side of the conversation, the app on the other side of the secret chat will be ordered to delete them as well.
You can order your messages, photos, videos and files to self-destruct in a set amount of time after they have been read or opened by the recipient. The message will then disappear from both your and your friend's devices.
All secret chats in SendChat are device-specific and are not part of the SendChat cloud. This means, you can only access messages in a secret chat from their device of origin.