Rivals of messaging service WhatsApp are experiencing a surge in popularity following the app's announcement of a new data-sharing agreement with parent company Facebook.
On January 6, WhatsApp informed its users outside the UK and European Union that they would lose access to their accounts on February 8 unless they agreed to let Facebook and its subsidiaries collect WhatsApp data that includes users' phone numbers, contacts' phone numbers, and locations.
Two years after WhatsApp was purchased by Facebook in 2014, users were given a one-time opportunity to opt out of sharing their data with Facebook. A spokesperson for Facebook told The Register that while this 2016 opt-out decision will be honored going forward, other users will not be offered the same choice over whether to share their data with Facebook.
In the days following WhatsApp's announcement, data gathered by app-analytics firm Sensor Tower revealed a 4,200% week on week increase in downloads of rival encrypted messaging service Signal.
"From January 6 to January 10, Signal saw approximately 7.5 million installs globally from across the App Store and Google Play," a Sensor Tower representative told Business Insider.
Over the same period, another encrypted messaging service, Telegram, experienced a growth of 91%, attracting 9 million new users.
The majority of new users of both apps were located in India, where 2.3 million installations of Signal and 1.5 million downloads of Telegram took place.
America, where around 1 million downloads occurred, accounted for Signal's second-biggest market.
Signal was recently endorsed by the world's richest man, Tesla billionaire Elon Musk, who posted a tweet to his 42 million followers on January 7 that simply read "Use Signal." On the same day, Freedom of the Press president Edward Snowden tweeted that he uses Signal every day.
The sudden increase in downloads caused a temporary slow-down of Signal's verification service.
On January 7, Signal tweeted: "Signal Verification codes are currently delayed across several providers because so many new people are trying to join Signal right now (we can barely register our excitement). We are working with carriers to resolve this as quickly as possible. Hang in there."