web.whatsapp.com FACT

Hope you are aware of whatsapp started web application that can be accessed on Desktop and Laptops as well. http://web.whatsapp.com/
I Started using web.whatsapp.com on my lappy using my WiFi connection and switch OFF my mobile data, web.whatsapp was not working but as soon as I switch ON the mobile data web.whatsapp started working.
So, web.whatsapp is using Mobile Data/Mobile WiFi connection instead of Laptop broadband or Wifi.