The mobile messaging service, which has over one billion users, said that it will share the phone numbers of its users with Facebook to provide “more relevant” advertisements and friend suggestions.
WhatsApp said in a blog post:
The company added: “By coordinating more with Facebook, we’ll be able to do things like track basic metrics about how often people use our services and better fight spam on WhatsApp. And by connecting your phone number with Facebook’s systems, Facebook can offer better friend suggestions and show you more relevant ads if you have an account with them.
“For example, you might see an ad from a company you already work with, rather than one from someone you’ve never heard of.”
Users will be able to opt out of sharing their information with Facebook, the company said, adding that “encrypted messages stay private and no-one else can read them.”
Pamela Clark-Dickson, principal analyst at Ovum, told the BBC:
“When WhatsApp was acquired by Facebook it was able to reassure users that it would remain independent.
“Now it’s giving Facebook phone numbers – some might say that’s a betrayal of trust. In a small way, it has gone back on what it said it wouldn’t do.”