Skype (/ˈskaɪp/) is an instant messaging app that provides online text message and video chat services. Users may transmit both text and video messages and may exchange digital documents such as images, text, and video. Skype allows video conference calls.
Skype implements a freemium model. Much of the service is free, but Skype Credit or a subscription is required to call a landline or a mobile phone number. At the end of 2010, there were over 660 million worldwide users, with over 300 million estimated active each month as of August 2015. At one point in February 2012, there were thirty-four million users concurrently online on Skype.