Robert Theaton, a software engineer in a blog wrote that the feature of the Whatsapp that allows us to see the person’s online status can be used to monitor the online activity of the user.
The contents of the messages cannot be read as when Whatsapp is end to end encrypted, but online status feature can be easily used to track the user’s activity timings on the application.
Robert wrote in the blog how easy it is for a computer expert to track the activities of any person using a four liner JavaScript code. The last seen option is one such feature about which most of the people doesn’t bother. So he wrote a command through which one can track the last seen settings of the user and create a pattern. However, where on one hand we still have a privacy option for last seen, there is no privacy option available for online status on Whatsapp.
If your Whatsapp number is saved in someone’s one then the person will be able to see if you are online on the app. You don’t necessarily need to have the stranger’s number saved on your phone.
Theaton has proved through his methods that even those people who are not in your contact can track you easily whenever you go online. This can also be used to track if two users are online at the same time. This still requires more code to be developed .Again, one cannot say surely that whether the person tracking others will be able to read their messages. But definitely he can build a usage pattern for the same. Whatsapp hasn’t commented anything regarding the same. Facebook messenger is suffering with the same problem.