The two-word Tweet from Elon Musk on Jan. 7 saying "Use Signal" has helped fuel millions in Signal and Telegram downloads. More importantly, Telegram, an instant messaging app with file transfer capabilities, has rocketed to the world's top app download.

Musk, the world's richest man, told his Twitter followers of more than 46 million to "Use Signal" last month amid concerns about an updated privacy policy for WhatApp.

On Jan. 12, days after Musk tweeted, Telegram said they "surpassed 500 million active users. 25 million new users joined in the last 72 hours: 38% came from Asia, 27% from Europe, 21% from Latin America, and 8% from MENA."