See Looking ahead for WhatsApp (WhatsApp blog) for the big-picture perspective; also see You can stop WhatsApp from sharing your phone number with Facebook (The Verge)
"WhatsApp announced the change to its terms of service policy today. It allows businesses to communicate with users, including appointment reminders, delivery and shipping notifications and marketing pitches. In a corresponding blog post, WhatsApp said it will be testing the features over the coming months.Facebook Takes First Step Toward Making Money From WhatsApp Deal - Bloomberg
The policy shift may help WhatsApp generate revenue, but also could irk users drawn to its strong stance on privacy. After it agreed to be purchased by Facebook in 2014, co-founder Jan Koum pledged the deal wouldn’t change how the company handles user data. Now WhatsApp says it will begin sharing more information about its customers with the "Facebook family." The data, including a person’s phone number, could be used to better target ads when browsing Facebook or Instagram, WhatsApp said."