The popular mobile messaging app will now be giving the social network its user data for ad targeting.

WhatsApp privacy is the catch users have been waiting to find. Mobile app users have wondered why WhatsApp suddenly changed from a premium application to a free one. The cost may not be in currency but will instead be in shared user data.

Facebook owns WhatsApp but has, until now, kept its fingers out of the user data files from the application.

Now, Facebook will be changing the level of WhatsApp privacy available to users. The mobile will share user data with Facebook for ad targeting purposes. Initially, it appeared that while there are certain controls being added to the mobile app’s settings, it isn’t possible to opt out entirely.

However, once a user has accepted the new terms and conditions for use of the app – a requirement for being able to use it – the mobile application automatically adds a new option within the settings for the account.  There, users can choose to opt out of the information sharing – a permanent choice that cannot be changed after it has been made.  That said, unless the users opt out, the mobile application will start sending some of the data in the account with the parent company.

This massive change was announced in a large update to the WhatsApp privacy policy.

WhatsApp Privacy PolicyA recent WhatsApp blog post said “[B]y 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.” Facebook will be better capable of showing more relevant advertising and improved friend suggestions, said the blog post.

Beyond Facebook itself, WhatsApp will also be sharing user data with the entire “Facebook family of companies.” This may include other Facebook acquisitions and firms, such as Oculus Rift, a virtual reality firm. That said, Facebook also owns Instagram, the photo sharing network, which may mean information will be shared there, too.

Among the user information to be shared under the new WhatsApp privacy policy is even the phone number used for account verification. This has already caused many users to bristle, with displeased comments appearing over Facebook and Twitter. There are certain pieces of information that consumers are more and less comfortable sharing openly. A telephone number does not typically fall within the category of the data they are pleased to see shared with unknown recipients.