Watsapp has become mostly used social app from last some years.It has become the part of life.The conversations become easy.The connectivity between peoples has increased we also can say that watsapp is bridge between peoples which keep connected them.
Iam using this aap last 4-5 years and I got good response when it was newly lauched we can only chat on it.after the upgrade we can call and do video free of cost.
I remember in early days the company charged 1msg for 1rs.and the photo sharing was also not possible.but when this app launch all the problems sloved.it is user friendly and the most important thing is it is fully trusted.