By Sebastian Herrera

WhatsApp is delaying a controversial update to its privacy policy following backlash from some users over how it would share data with Facebook Inc., which owns the popular messaging service.

The company said its roughly two billion users would have until May 15 to review and accept the new policy, which is when the data changes are set to go into effect. If users don't consent by then, the app will eventually stop working for them, a spokesman said. The previous deadline for accepting the changes was Feb. 8, but WhatsApp said it would "go to people gradually to review the policy at their own pace."

"We've heard from so many people how much confusion there is around our recent update," a WhatsApp spokesman said. "There's been a lot of misinformation causing concern and we want to help everyone understand our principles and the facts."

WhatsApp said the new policy isn't geared to expanding its ability to share data with Facebook but rather to allowing businesses that interact with customers on WhatsApp to store those conversations on Facebook servers. The move was a key step in Facebook's plan to generate revenue with the app after many years of struggling to do so. Businesses will also be able to store user shopping activity on the servers.

The apparent user resistance and confusion about the new policy point to the difficulty the service faces in advancing on a profit-generating path. Even as WhatsApp remains a market leader in messaging, the competitive landscape for private, encrypted messaging platforms is intensifying. Privacy concerns are growing as a key consideration for users.

"A lot of folks didn't make the connection that WhatsApp was owned by Facebook, so being more forthcoming in that relationship was really a strike against WhatsApp," said Ashkan Soltani, a former technologist for the Federal Trade Commission. "It has become important to Facebook that the current model of social media is risky with content moderation and privacy law. So they are pushing to find additional ways to monetize."

Certain users expressed uncertainty last week on social media about the new policy and questioned whether the changes would allow Facebook to access messages or other information they had believed was private. Memes depicting WhatsApp as an open network spread quickly through social media. A tweet by Tesla Inc.'s Elon Musk urging his followers to use messaging app Signal generated more than 59,000 retweets.

The company has faced substantial backlash in Turkey, with the government telling its citizens to drop WhatsApp and use Turkish apps such as BiP. WhatsApp said it is sending users in Turkey virtual cards outlining the app's privacy.

The company said it plans to remind all its users that WhatsApp messages are protected with end-to-end encryption and that neither WhatsApp nor Facebook can see the private messages, keeps logs of whom users are calling or messaging, see a shared location or share user contacts with Facebook.

Some data between the two companies has already been shared for some time. Facebook is able to see which phone numbers are being used in WhatsApp, how often the app is opened by users and their mobile carrier.

While WhatsApp this week sought to clarify the policy and offer assurances about privacy, users have begun to look elsewhere.

Jeremiah Gassensmith, an associate professor of chemistry and biochemistry at the University of Texas at Dallas and longtime WhatsApp user, said he decided to leave the messaging service after seeing the notices about the privacy settings overhaul. He is now using Signal instead.

Facebook's compilation of user data had been a concern and his worries escalated in recent years as the company sought more integration with its other apps such as Instagram and WhatsApp.

"It seems like Facebook is gradually bringing down the walls between you and your data," Dr. Gassensmith said. "I can't buy it any longer."

WhatsApp downloads globally decreased by about 17% in the week after its new policy announcement compared with the week before across Apple and Google's app stores, according to app analytics firm Sensor Tower Inc. Meanwhile, downloads of Signal during the same period increased by about 6000% and downloads of Telegram, another service, more than doubled, according to Sensor Tower.

Write to Sebastian Herrera at Sebastian.Herrera@wsj.com

(END) Dow Jones Newswires

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