The Instant messenger reference article from the English Wikipedia on 24-Jul-2004
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Instant messenger

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An instant messenger is a computer application which allows instant text communication between two or more people through a network such as the Internet.

Table of contents
1 Overview
2 Cooperation
3 Protocols
4 Clients
5 Servers
6 See also
7 External links

Overview

An 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 convey an "online status" between users, such as if a contact is actively using the computer. 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 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).

Instant messaging has 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.

On December 19, 2002, AOL Time Warner announced that they 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.

Cooperation

There 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), and the open XML-based XMPP (Extensible Messaging and Presence Protocol), more commonly known as Jabber.

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, and Miranda IM. Jabber 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.

The networks utilized by multi-network IM clients have been silent, except for .NET Messenger (formerly known as MSN Messenger) and AOL Instant Messenger.

The count:

MSN-- 2 problems for Trillian that Microsoft did not volunteer help on, the last one was intentional, and came right before the Yahoo move. The other was not necessarily intentional. And when Microsoft changed their protocol the last time, they informed Cerulean Studios which released a fix before any disruption could occur. Microsoft said it was seeking "formal agreements" from third party vendors as it mandated upgrades to v.8 of its protocol in order to connect to its network.

AOL- AOL and Trillian played "cat and mouse" for a while, with Cerulean Studios having to release about 5 revisions (with at least 3 of them being patches), sometimes finding it more convenient to package it into its next and imminent release(s).

But on September 26, 2003, Yahoo! made changes to its instant messenger fully aware that it might prevent users of Trillian from using their network to communicate. Like Microsoft, they also cited security concerns, rather than the need to block third party clients. The changes to the login process, however, simply obfuscated the seed value sent from Yahoo to the application, and both reply values sent back to authenticate the user, by making them resemble mathematical expressions and assignments. This red herring (fallacy) provided little extra security, but does make the login process harder to reverse engineer. The changes not only prohibited connection to Yahoo!'s IM network, it also caused the Trillian client to crash. Yahoo! announced they would continue to work to prevent other clients from using their network. Cerulean Studios, the makers of Trillian, said they would continue to seek ways to use Yahoo's IM infrastructure.

In early 2004 Yahoo again altered its authentification process, by activating a part of the algorithm which had remained dormant. Again third party software responded with updates within days of the change. Currently, as of 2004, Cerulean has released patches which fixes the Y!M attempts to block out it as a client.

Protocols

Clients

Servers

See also

External links