The phone number associated with a user’s WhatsApp account will be used on Facebook to show them ads. This will form part of the targeting the company allows for paying advertisers, who can upload contact databases. Those who use Facebook and are in the contact database uploaded by the advertiser will then be shown the targeted ads.

The information will also be used to show how people interact with a specific ad, but Facebook said that it would not tell advertisers who specifically interacted with the ad.