Glossary » instant messaging
instant messaging
IM; a technique of sending a message: the sender specifies the recipient and typically types a simple text message; the recipient has a window pop up automatically that displays the short message. This differs from email in that the interface is usually designed only for short messages and because the message is intrusive – it interrupts whatever the recipient is doing, whereas an email usually arrives in the background and is viewed at the recipients leisure. An instant message differs from chat systems in that the recipient does not explicitly start the application and the communications are private.