Skype is the most popular free voice-over IP and instant messaging service globally. It allows users to text, video and voice call over the internet. Users can also call landlines and mobiles at competitive rates using Skype credit, premium accounts and subscriptions. Skype was publically released in 2003 and now accounts for roughly a third of all international calling minutes. Skype uses P2P technology to connect users on a multitude of platforms including desktop, mobile and tablet. The call quality (depending on your internet signal) and additional features like conversation history, conference calling and secure file transfer are excellent. There have been some criticisms over the programs bandwidth usage and security vulnerabilities.
Skype’s UI is very intuitive and easy to use. All the classic messaging service features like profiles, online status, contacts and recent history are displayed in the left navigation. Here you will also find the Skype directory, group options, a search box and premium calling buttons. The right side (main window) opens the content you select. For individual contacts you will see a text message box, chat history and calling options.