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Instant messengerAn "instant messenger" is a client which allows instant text communication between two or more people through a network such as the Internet.
OverviewAn instant messenger is a client which hooks up to an instant messaging service. Instant messaging differs from e-mail in that conversations happen in realtime. Also, most services offer a "presence awareness" feature, indicating whether people on one's list of contacts are currently online and available to chat. Generally, both parties in the conversation see each line of text right after it is typed (line-by-line), thus making it more like a telephone conversation than exchanging letters. Instant messaging applications may also include the ability to post an away message, the equivalent of the message on a telephone answering machine. Popular instant messaging services on the public Internet include Jabber, AOL Instant Messenger, Yahoo! Messenger, .NET Messenger Service and ICQ. These services owe many ideas to an older (and still popular) online chat medium known as Internet Relay Chat (IRC). An early form of instant messaging was implemented on the PLATO system in the early 1970's. ICQ was the first general instant messenger introduced to the internet, in November 1996. After its introduction, number of variations of Instant messaging have arisen in parallel in many places, and each application has its own protocols. This has led to users running many instant messaging applications simultaneously to be available on several networks. Alternately they could use a client which supports many protocols, such as Gaim or Trillian. Recently, many instant messaging services have begun to offer video conferencing features, Voice Over IP (VoIP), and web conferencing services have begun to integrate both video conferencing and instant messaging capabilities. Hence, the boundaries between these media have become blurred. On December 19, 2002, AOL Time Warner announced that ICQ had been issued a United States patent for instant messaging, but they also said that they had no plans on enforcing their patent at the present time. The term "instant messenger" is a Service Mark of AOL Time Warner and may not be used in software not affiliated with AOL. For this reason, the instant messaging client formerly known as GAIM or gAIM is now only to be referred to as Gaim or gaim. Origin of termThe phrase "instant message" was devised by Paul A. Linebarger for a gimmick in the science-fiction stories he wrote in the 1960s under the pseudonym Cordwainer Smith. His instant messages were to be across interstellar distances at speeds faster than that of light, and said to be expensive so he could write plots concerning their unaffordability. From there, the phrase was picked up by members of New England Science Fiction Association, many of whom were computer professionals, for their weekly mimeographed newsletter. The phrase may have come from there. CooperationThere have been several attempts to create a unified standard for instant messaging: IETF's SIP (Session Initiation Protocol) and SIMPLE (SIP for Instant Messaging and Presence Leverage), APEX (Application Exchange), Prim (Presence and Instant Messaging Protocol ), the open XML-based XMPP (Extensible Messaging and Presence Protocol), more commonly known as Jabber and OMA(Open Mobile Alliance)'s IMPS (Instant Messaging and Presence Service) created specifically for mobile devices. Most attempts at creating a unified standard for the major IM providers (AOL, Yahoo! and Microsoft) have failed and each continues to use its own proprietary protocol. Some instant messaging applications attempt to combine the many disparate protocols into a single, unified client. Examples include Trillian, Gaim, Fire, Proteus, Miranda IM, Adium, Everybuddy , Ayttm, Kopete, Centericq and BitlBee. The Jabber/XMPP protocol takes a somewhat different approach, moving the task of communicating to the other services to the server, allowing clients to be simpler and waste fewer resources. Also, this way all Jabber clients are intrinsically interoperable with other networks. Some approaches, such as that adopted by the Sonork enterprise IM software or the Jabber/XMPP network, allows organizations to create their own private instant messaging network by enabling them to limit access to the server (often with the IM network entirely behind their firewall) and administer user permissions. Typically, a dedicated corporate IM server has several advantages such as pre-populated contact lists, integrated authentication, and better security and privacy. Some networks have made changes to prevent them from being utilized by such multi-network IM clients. For example, Trillian had to release several revisions and patches to allow its users to access the MSN, AOL, and Yahoo networks, after changes were made to these networks. The major IM providers typically cite the need for formal agreements as well as security concerns as reasons for making these changes. Servers
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