"Instant messaging", or "IM", refers to electronic communication wherein short text messages are sent and received in "realtime" (i.e. with a very short delay or "lag time" – usually 1 second or less – between the sending and the receipt). It most commonly refers to the various IM services such as AIM, Yahoo!, MSN, and ICQ, but can also refer to IRC.
Text-paging on a cell phone (especially if the recipient is equipped to send back a text message in reply) is also sometimes referred to as IM, but the lag time for such messaging is usually rather longer (seconds to minutes).
- 2008-05-15 Instant messaging 'a linguistic renaissance' for teens: "In a paper to be published in the spring 2008 issue of American Speech, the researchers argue that far from ruining teenagers' ability to communicate, IM lets teenagers show off what they can do with language."