WhatsApp will start sharing users phone numbers with Facebook, and you have only 30 days to opt out.
Apart from stepping on your privacy, it also means that you will start seeing more targeted ads and Facebook friends suggestions, all based on your WhatsApp information.
WhatsApp users of course have the option of opting out, but you have to make an effort to uncheck a box in order to do so. Users have 30 days to accept the new policy terms, or to stop using the service. If you accept, you have 30 more days to opt out of sharing with Facebook.
However, WhatsApp promises that Facebook will not post any phone numbers online. They also assure us that encryption will remain, so neither WhatsApp nor Facebook would have access to your messages.
[Source]
