Skype () is a proprietary telecommunications application operated by Skype Technologies, a division of Microsoft, best known for IP-based videotelephony, videoconferencing and voice calls. It also has instant messaging, file transfer, debit-based calls to landline and mobile telephones (over traditional telephone networks), and other features. It is available on various desktop, mobile, and video game console platforms. Skype was created by Niklas Zennström, Janus Friis, and four Estonian developers, and first released in August 2003. In September 2005, eBay acquired it for $2.6 billion.
https://en.wikipedia.org/wiki/Skype