Skype is a proprietary Voice over IP service and software application. First released in 2003 written by Estonian developers Ahti Heinla, Priit Kasesalu, and Jaan Tallinn, who had also originally developed Kazaa. Since 2003 it has become a very popular application with 600 million users world wide. It 2011 it was purchase be Microsoft for $8.5 billion.
Skype enables it users to communicate with text chat, voice or even video from computer to computer anywhere in the world for free. For a small fee you call call from your computer to any phone anywhere in the world. Skype also has smart phone Android and iPhone apps that make it possible to connect a Skype user form your mobile device.