WhatsApp was founded in 2009 by two former Yahoo employees, and slowly evolved into the most popular mobile phone messaging application. The salient advantage of WhatsApp was that one could sent unlimited free messages with an internet connection, ending the reliance on SMS that are charged at a per message rate by telecom operators. Though iMessage existed for Apple customers and Blackberry messenger for Blackberry customers, these could only be used if both parties communicating owned a device of the same company. With the advent and increased popularity of the Android operating system developed by Google, anyone could have access to encrypted private messaging through WhatsApp, which previously only Apple and Blackberry customers could enjoy, by downloading the application on any kind of device.
This freedom from SMS costs and secure messaging made WhatsApp wildly popular, and by 2014, Facebook bought it for a staggering $19 billion, the highest amount ever paid for an acquisition till then. For the sake of comparison, Facebook had bought Instagram for $1bn just two years before buying WhatsApp.
It is indeed a blunder by WhatsApp to move towards a model that is less private than before.
There has also been mass migration towards more secure applications. It is pertinent to note that currently the application that is considered most secure is the Signal application, which is run by a nonprofit venture called Signal Foundation started by cofounder of WhatsApp Brian Acton who had left WhatsApp in 2017. In 2018, WhatsApp’s CEO and cofounder had also left the company, allegedly due to disagreements with the direction in which Facebook was taking the application.
Signal is an open source application, which means no corporation has total control over the software, and all user information is end-to-end encrypted, except for the contact information required to sign up for the application, which is also not kept as personally identifiable information by the application. The other application is Telegram, where the data collected includes contacts and device and network identifiers.