WhatsApp rival Telegram has seen a 500 percent increase in new users, following dissatisfaction with the way Facebook-owned WhatsApp handles people's data.
Telegram registered 25 million new users in the last 72 hours, according to founder Pavel Durov, taking the total number of users over 500 million.
That's roughly a quarter of WhatsApp's 2 billion users worldwide, though many users of the world's most popular messaging app went on social media this week to push others off the platform, due to concerns of privacy.
WhatsApp sent a notification to all its users, forcing them to accept its privacy policy, which includes terms for sharing data with Facebook.
The Terms of Service update, which takes effect on 8 February, does not apply to users in the UK and Europe, but has led to considerable criticism from users, privacy advocates and competitors.
Mr Durov, who has often criticized WhatsApp's approach to user privacy in the past, said on Tuesday that "the recent rise of new users was the most significant in the company's seven-year history".
"People no longer want to share their privacy with free services. "They no longer want to be held hostage by technology monopolies that seem to think they can get away with everything as long as their applications have a critical mass of users," he wrote.
"With half a billion active users and accelerating growth, Telegram has become the biggest haven for those looking for a communication platform dedicated to privacy and security. We take this responsibility very seriously. We will not disappoint you. "
Mr Durov added that since its inception in August 2013, Telegram "has not disclosed any bytes (bits) of users' private data to third parties".
Other rival messaging apps also saw an increase in new users this week, including Signal , which was slightly overloaded by the influx of new downloads.
Data from analytics firm Sensor Tower revealed 8.8 million new downloads for Signal this week.
"We continue to break traffic records and increase capacity as more and more people agree that they do not like Facebook's new terms," ??Signal wrote on Twitter. "If you have not been able to create a new group recently, please try again. The new servers are ready to serve you."
Source: The Independent