Along with the boom in smartphones around the world, instant messaging applications created by technology tycoons or startups have been downloaded in almost every mobile device. The main reason why these apps are such a big hit with users is because they are easy to use and, more importantly, free.
WhatsApp
WhatsApp Messenger is a cross-platform mobile messaging app that allows users to exchange messages without having to pay for them.
On February 19, 2014, Facebook Inc. announced it was acquiring WhatsApp Inc for $19 billion. Currently, it has 450 million active monthly users, according to the company.
Day|Week|Month