Skype
Skype is a popular messaging app and service that enables users to communicate with each other via voice, video, and text chat. It allows for free international calls to landlines and mobiles in over 200 countries, and also offers low-cost calls to other countries. Skype also offers an array of features such as group video calls, instant messaging, file sharing, and even a marketplace where users can buy or sell goods and services. Skype also includes end-to-end encryption, ensuring that conversations remain private and secure.