Just one month into the new year and Facebook is already facing a new exodus from users over changes to privacy settings in its messaging arm WhatsApp.

The outrage has become so widespread that downloads of its major rival have spiked more than 4200 per cent and won an endorsement from the world's richest man.

But should you be ditching WhatsApp for Signal or Telegram? How long do you have to make the switch? And what are the consequences if you keep using Facebook's green app?

We've broken down the changes to the messaging world for you.

What is the controversy around WhatsApp?

The messaging app was snapped up by Facebook for $US19 billion in 2014, making it the social network's largest acquisition to date.


WhatsApp users expressed concern at the purchase, given Facebook's reputation for privacy, but its founders stayed with the company and assured users it would not be used to sell ads.

In 2016, WhatsApp began sharing data with Facebook by default but allowed users to opt out of this transaction.

The latest proposed changes go much further, however.

Facebook initially gave WhatsApp users until February 8 to accept changes that would see their information shared with Facebook and threatened to suspend WhatsApp service for them until they agreed.

That deadline has now been shifted to May but the app still delivers pop-up reminders, asking users to accept Facebook's new terms and conditions.


What is changing in WhatsApp?

New additions to WhatsApp's terms of service would see information from its users shared with Facebook and its "family of companies".

The new policy states: "We may use the information we receive from them, and they may use the information we share with them, to help operate, provide, improve, understand, customise, support, and market our services and their offerings."


The information shared from WhatsApp to Facebook will not include the content of users' messages - they are encrypted and will remain private.

It will, however, include metadata that shows who you're communicating with, where you are, and what device you're using, and it can also share your mobile phone number with Facebook.

It could potentially share your contacts with Facebook, though WhatsApp has disputed this in a message to users.

Facebook has also sought to clarify what its changes mean, telling users they were designed to allow "new options … to message a business on WhatsApp" and allow shopping inside the messaging app in future.


When do WhatsApp changes occur?

Users have until May 15 to accept the privacy policy changes to WhatsApp and, until that date, they can keep dismissing the pop-up warning about them.

After that date, however, WhatsApp users will have to accept Facebook's new requirements or stop using the app.


Isn't this exactly what WhatsApp was designed to avoid?

Yes. Former Yahoo employees Brian Acton and Jan Koum created WhatsApp in 2009 as a way to share messages privately.

Before being taken over by Facebook, the apps mantra was "No ads! No games! No gimmicks!"

Mr Koum also reportedly got Facebook executives to agree to allow WhatsApp to operate independently and ad-free as part of the deal.

He left the company in 2018, reportedly after stoushes over these issues.


What is Signal's story?

Perhaps ironically, Signal was launched in 2018 after $US50 million in funding from WhatsApp co-founder Acton.

He left WhatsApp and Facebook in 2017, a year after his co-founder, and was so passionately opposed to offering advertising in WhatsApp, he left a year before his stock grants vested, costing him $US850 million.


As such, the Signal Private Messenger app promises to deliver users free and private messages, voice calls, video chats, voice recordings, and group discussions, protected by end-to-end encryption.

And, in a potential dig at its major competitor, the company states it features "no ads, no affiliate marketers, no creepy tracking".

"Privacy isn't an optional mode - it's just the way Signal works. every message, every call, every time," the company says in app stores.

For users who install the app on Google Android smartphones, Signal can also be used as the phone's default messaging service in place of SMS.


Why do people trust Signal more than WhatsApp?

Signal recently received some high-profile endorsements.

The world's richest man, Tesla boss Elon Musk, tweeted the simple message "Use Signal" earlier this month, sparking 61,000 retweets.

There was some confusion, however, with a similarly named company - Signal Advance - that received a stock price boost after this tweet.

Whistleblower Edward Snowden - a man with a vested interest in keeping his messages private - also endorsed the real Signal messaging firm, saying he uses its services every day.

Signal also receives its funding from grants and donations rather than advertising, and uses open-source software.

It has risen to the top of Apple and Google app stores over the past month, with app analyst firm SensorTower saying Signal experienced a 4200 per cent growth in just one week in January, registering another 7.5 million installations.


Is Telegram a better option?

Another app competing with WhatsApp and gaining a lot of users over the past week is Telegram, which boasts more than 500 million active users.

It promises to deliver messages and let users send disappearing text, photos and videos free to charge.

Importantly, however, Telegram doesn't offer end-to-end encryption for its messages by default. That protection is only offered in "secret chats" that bypass Telegram's cloud.

Despite this, Telegram's popularity is also soaring in the wake of WhatsApp's announcement, up 91 per cent or nine million downloads.

Originally published as Why people are leaving WhatsApp