In that way, as they say from WhatsApp, the People You May Know option on the Facebook network will be upgraded, but it is ‘clear as a day’ that this way of personal information exchange between WhatsApp and Facebook is done mostly because of the ads. This means that on WhatsApp there will be payed, i.e. ‘sponsored’ profiles (from Facebook) that will allow brands, stores and such to communicate directly with the WhatsApp users.
From WhatsApp say that, they will be exchanging messages with the Facebook network, and as well as with other “sister companies” like Oculus, Instagram and Boomerang and other apps in property of Mark Zuckerberg and his closest business partners.
All the information that will be exchanged with Facebook and other social networks wont be visible for the other users, i.e. they wont be published, and they could and would be used to fight the “spam” messages, social network abuse and similar.