Exchanging text messages in real time between two or more people logged into a particular instant messaging (IM) service. Instant messaging is more interactive than email because messages are sent immediately, whereas email can be queued up in a mail server for seconds or minutes. However, there are no elaborate page layout options in instant messaging as there are with email. The basic operation is simple: type a brief message and press Enter.
Instant messaging services may also provide video calling, file sharing as well as PC-to-PC or PC-to-phone calling. Some services can switch from "text chat" to "voice chat" for users with a headset or microphone.
In order to set up an instant message, you have to add the usernames of the people you want to message with to your "buddy list" (friend list, contact list). When they log in to the Internet with their IM software, and provided they have not configured themselves as "invisible," you are instantly alerted. When they log out, you are also notified. Each system has its own method for blocking incoming and outgoing messages.
The IM Services
Instant messaging (IM) became popular after Israeli-based ICQ introduced its service in 1996, which was later acquired by AOL. Examples of major IM services are Google Talk, Facebook Messenger, Snapchat and Skype.
Although third-party IM clients such as Trillian and Simple Instant Messenger were designed to interface with multiple IM services, the client programs from the IM service were always proprietary to that service. Google changed that practice by basing Google Talk on the open XMPP protocol used in Jabber (see XMPP
). See IRC
, chat room
, voice over IM
, Google Talk
Short and Sweet
This Google Talk snippet is a typical text interaction. The user's picture can be real or selected from a list (see avatar
). In this example, Alan used a real photo, while Lynn preferred the smiling monkey.