As per WhatsApp:
"We're excited to share that, as of today, WhatsApp supports more than two billion users around the world. Mothers and fathers can reach their loved ones no matter where they are. Brothers and sisters can share moments that matter. Coworkers can collaborate, and businesses can grow by easily connecting with their customers. Private conversations that once were only possible face-to-face can now take place across great distances through instant chats and video calling. There are so many significant and special moments that take place over WhatsApp and we are humbled and honored to reach this milestone."