Any application or internet site that is popular is going to make money. Getting a popular site or app always helps the company who created that item. Either the company sells a product, requires the users to pay for a subscription or sometimes the app is completely free to its users. However, the company gets money by having ads placed on their site. Other companies want people to see their products and so they will advertise on other sites or apps.
In the case of WhatsApp, they wants to have an instant messaging system that did not break the bank. For WhatsApp, they provide a subscription. They allow people to use the system free for a year. Then after that, it costs relatively nothing – only one dollar.
