ASL STEM

Definition

messaging program that uses peer-to-peer networking over the Internet to let users send messages instantly to people on a buddy list. As well as allowing text to be sent, IM enables voice chat, videoconferencing, SMS (short message service) paging, and shared access to documents, files, and pictures. The first instant messaging program was ICQ, released in November 1996, and bought in June 1998 by America Online, which had already launched its own IM service in May 1997. Yahoo launched a service in 1998 and Microsoft in 1999. These IM services are normally incompatible, but a program called Trillian allows users to chat to friends on all of them concurrently.

Source: Hutchinson Dictionary of Computing and the Internet. Abingdon, Oxfordshire, GBR: Helicon Publishing, 2005. p 282.