In the privacy domain, there have been concerns related to user metadata as well. WhatsApp encrypts the communication channel between users using end-to-end encryption. The metadata of the user is encrypted as well when data is in motion on the communication channel between various parties. It is essential to understand that information stored in metadata is just as important in preserving privacy of the users, as is the data itself. The company's legal terms allow them to store information associated with successfully delivered messages such as time of delivery, mobile phone numbers involved in the messages, size of any digital content swapped between the two parties (Bernstein 2006). Also, the app persists the user to share one's entire contact list with the app. This is a way to further gather information about who is in a particular social network of a user. It is like trading the convenience of having the app to figure out who uses it amongst one's contacts for giving up the entire list of which one contacts regularly, including those who don't use the app. There is still no option of selectively adding contacts to the WhatsApp list. Any addition of this feature in the future will not help existing users as they have already shared this detail with the app.

A smartphone metadata reflects a wealth of details both at the level of individual calls and when analyzed in aggregate. Computer scientists and researchers have proved this a number of times in the past. It is here where WhatsApp falters. While the metadata is encrypted during transit, phone numbers, timestamps, connection duration, connection frequency, as well as user location are being stored on the company's servers. This metadata is sufficient to create a profile and draw some strong inferences between the communicating parties. And as we've seen very often, both governments and hackers can get their hands on the metadata if they realty go after it.

What advantage would Facebook, the parent company has in addition to the metadata related information coming via WhatsApp? WhatsApp had vowed that it would not be selling advertisements. However, there is no condition that can stop its parent company from doing so by using information gathered through the whatsapp. In combination to one's activities on Facebook, it can potentially help create a more accurate understanding of the user behavior, and social interactions thereby serving as a strong measure of profiling for some targeted ads. This is not truly a major concern as long as the user sees ads that make sense to them. Any change in the content delivery algorithm can lead to a very different user experience, where in some cases the user may outright stop using the app.

For group chat, the communication initiator sends message to the whatsapp server, which in turn distributes it to all the group members. This is a very easy way of for Facebook to learn all about ones social interactions and communities. A lot can be deduced by performing some kind of traffic analysis just by using the metadata like from the message volume exchanged.

In August 2016, WhatsApp changed its terms of privacy where it stated that it plans to transfer user data to its parent company, Facebook. It had earlier promised that this data would not be disclosed or used for marketing purposes. But now it will share user account information with Facebook and the Facebook family of companies, like the phone number the user used as a primary identifier. The companies intend to use WhatsApp account information to show users "more relevant ads on Facebook" and to send users marketing messages via WhatsApp. A phone number is like a digital social security number (EPIC - WhatsApp). It can uniquely identify a person as this information is provided every time when filling up forms for various purposes. It can also connect various sources of data, like health records, financial data, and education, online presence, etc. and create a full profile of a person.