WhatsApp announced this news in their blog, also, they clearly stated that they don’t display third party ads in WhatsApp.
we’re happy to announce that WhatsApp will no longer charge subscription fees
Also, they are planning to allow WhatsApp to communicate with businesses and organizations according to your interest. That is you can communicate with your bank account about the last transaction is a success or not, also you can check with your airline about a delayed flight, the possibilities of WhatsApp and businesses are high.
In Future, we can expect the text messages from various services are sending through WhatsApp.