Mobile messaging apps are more popular than ever as they add social networking features, improve security, and compete to meet the demand for free mobile calling and texting services. Established mobile apps like Facebook Messenger, Apple's FaceTime and Messages, and internet calling services like Skype, still dominate, but they have a pack of promising competitors. Almost all mobile messaging apps offer some form of free voice or video calling , and free mobile texting, over both Wi-Fi and the user's data plan. 1.WhatsApp The enormously popular WhatsApp is a mobile text messaging app designed for smartphone users and tablets that lets you send text messages and make calls over the internet. WhatsApp is really easy to understand and there isn't lots of "fluff" to make it overwhelming like some apps. You can even set a status for all your contacts to see without having to message everyone. WhatsApp also lets you share your locat...