instant messaging

n. (IM, abbr.) A private, synchronous exchange of messages between parties over a computer network. A system for allowing instant message sessions.


Instant messaging (IM) requires users to subscribe to an IM service and run service-specific software. Because of competing standards, the parties must use the same service and application to be able to participate in instant messaging sessions.Instant messaging allows users to chat in real time. Unlike email, both parties must be simultaneously connected to allow messages to be exchanged. Although most IM services are restricted to plain text, some allow users to send attachments. Unlike email, many IM services are similar to phone calls in that they create no record that documents the content of the communication. However, some IM systems are designed to record the content.